Goodness, I'm on something of a SI roll! Anyways...This is my contribution to the whole "Do I, or do I not ignore so-and-so's suffering, when I can do something about it, in the name of preserving my foreknowledge?"
My answer? Hell no, I don't! NOT when it's a kid, and especially when it's a kid that's being neglected and/or borderline abused like Naruto or Tsuna. While I can understand the motivation behind keeping the timeline as close to canon as possible, in this kind of situation it doesn't outweigh the kid in question.
**It's perfectly acceptable to write a SI-story where the SI does decide to ignore the kid, and I mean no disrespect to the authors who take that route, but any insert of me wouldn't go along with it when it's a kid. Kids hit certain buttons with me that others don't.

Yamada Kaneru is six years old when her parents' jobs have them packing up to move to a small town called Namimori. Her parents heave unseen sighs of relief at how she dutifully refrains from kicking up a fuss, because their coworkers who had done the same had shared their experiences, and they had dreaded the outcome. They praised their daughter for being so well-mannered, so sweetly behaved during the preparations and the move, and gave themselves an internal pat on the back for rearing her properly.

In reality, Yamada Fukuko and Fusao are very distant parents indeed. They are hard-working and devoted to their jobs, but little of that devotion and attention is ever directed towards their daughter. Yamada Kaneru has been looked after primarily by a steady stream of babysitters and nannies, each one being swapped out when they began hinting to her parents that perhaps they should take some time off. By all rights, they should have had a spoiled hell-raising brat, one that would kick up an unholy fuss at every turn for their attention.

Yamada Fukuko and Fusao will never know how they lucked out when they got Kaneru as their daughter. Kaneru was on her second life and perfectly capable of looking after herself.

Initially, Kaneru hadn't had any idea what had happened to her. She had gone to sleep a twenty year old woman, happy and healthy, and the next thing she knew she was experiencing the miracle of birth for the second time. She still had the occasional nightmare about that, and a smidge of claustrophobia.

How she had died was an utter mystery to the woman-turned-child, but she guessed she had died in her sleep for whatever reason. Kaneru just counted her blessings she had been unconscious during whatever had caused her to shuffle off the mortal coil, and turned her focus to dealing with her current life.

Once she was old enough to have left the degrading and demoralizing experience of infancy, and had learned some Japanese, Kaneru had started investigating to figure out just where and when she had been reincarnated. She had already known she hadn't been born into any place that hadn't seen the Industrial Revolution, and the technology matched what she remembered growing up with in the 1990's. Kaneru had also known it was very likely she had been reborn in Japan, or a country where Japanese was the predominant language. A little digging revealed that she had been quite accurate in her deductions.

Yamada Kaneru had been born in Japan, in Tsuruoka to be precise, and the year was 1998. She had instantly found the whole thing extremely suspicious. Considering that in her first life she would still be alive, and three years old, since she had originally been born in 1995 instead of 1992, Kaneru highly doubted everything was as normal as it appeared to be. Unless souls could reincarnate whenever they pleased, and have two versions of itself in the same reality… Kaneru had carefully decided to not pursue that line of thinking for her own sake.

Namimori had been a familiar name, and Kaneru hadn't been able to hide her surprise at the fact they were actually moving to a place called Namimori. Her mind had boggled at the ludicrous idea she might have somehow wound up in a manga, but Kaneru had doubted she was actually moving to the setting of that wacky story. It was possible the author had taken the name from an actual place, or Namimori had changed its name to avoid association with the manga, or anything along those lines.

And once they had arrived and moved in, Kaneru had heaved a sigh of relief that there hadn't been any streaking boys or grenade explosions even once since they had entered Namimori. She had relaxed, anxiety unwinding at the tentative reassurance she hadn't been reborn into a world where the godforsaken mafia had acquired superpowers. But then her parents had pulled a fast one on her, by entering her into what was left of preschool. She hadn't been expecting that, and she thought her parents had realized by now she was much, much more advanced than any six year old. Kaneru could've jumped into first grade easily when the school year started, but Fukuko had convinced her husband that she needed to socialize with her new peers to further her successes later in life. Or something like that. Kaneru had ceased to listen after she had confirmed she was going back to preschool immediately.

So when Monday came, Fusao had bustled her off to her new preschool (rarity of rarities for him to do it himself,) and escorted Kaneru to her guide before rushing off before she could so much as say "Bye." The guide hadn't looked pleased with Fusao's actions, but Kaneru had prodded her into action by pointing out she was going to be late if she didn't get to class soon.

The woman had gotten her act together then and shuffled off to her new homeroom. The woman to be her new teacher took her off the guide's hands and introduced herself.

"Hello there! Kaneru-chan is it?"

Kaneru had bristled at her, taking umbrage to her presumption.

"It is Yamada-san, sensei, or Yamada-chan if you prefer."

That had shocked her.

"O-oh, I see Yamada-chan. Please call me Midori-sensei, or Tachibana-sensei if that's more to your liking. Now Yamada-chan, while it's pretty late in the year, I would like you to introduce yourself to the class anyways."

Kaneru hadn't liked the idea, because she had discovered this meant she would be absolutely peppered with questions until the teacher let her escape, but she nodded anyways. The woman had changed to addressing her properly, so there hadn't been a need to continue being shirty with someone she wouldn't ever see again after preschool ended.

Midori had then escorted her into the classroom, the kids quieting down pretty quickly when they saw Midori was behind Kaneru.

"Alright class! This is Yamada Kaneru, she's just moved here from Tsuruoka and she will be joining our class from now on! Please introduce yourself to your classmates Yamada-chan."

Kaneru bowed.

"Hello, my name is Yamada Kaneru. I like reading. You may call me Yamada-san or Yamada-chan."

Then she metaphorically hunkered down to weather the incoming hailstorm of question. They asked about everything from her clothing, her hometown, to the move, with Kaneru keeping her answers as concise as she could. Whenever one of the kids worked up the courage to ask something personal or something mocking, Kaneru coldly snubbed the brat in question and refused to answer whatsoever. The kick in the teeth came from the final questioner, a kid in the very back of the class.

"Alright everybody, this is the last question for Yamada-chan! Sawada-kun, go ahead, you've been waiting patiently."

Kaneru's attention had been drawn to the name Sawada with all the concentration she hadn't been displaying since she had entered the class, because she had to see if it was a coincidence. She hadn't paid attention to the children, and now she hunted for a head of fluffy hair. And lo and behold, she spotted the quivering caramel fluff and had her worst suspicions confirmed. She couldn't help but think, Oh sweet buggering fuck, before he worked up his nerve.

"U-um, Y-yamada-san, Tsu-kun wanted to know…D-do you like robots?!"

Kaneru was already stunned to actually find Sawada Tsunayoshi was now a real little boy, but the fact he had managed to shout out his question when he was such a shy thing surprised her even more. She apparently had been silent for too long, because the kid started to blush ferociously and wilt in a very distressing manner, all while the class began to laugh at him and call him "Dame-Tsuna!"

Kaneru narrowed her eyes at the laughing children before turning to Midori and tugging on her pant leg harshly.

"Make them stop."

Midori looked down at her strangely, but the woman humored her again and called the class to order.

"Alright Yamada-chan, you can-"

Kaneru glowered at the woman.

"I didn't get to answer Sawada-san's question Tachibana-sensei."

"Ah, Yamada-chan-"

"Why can't I? His was a good one."

Her pronouncement had the class join Midori at staring at her like she was an alien, though Kaneru didn't know why on earth the teacher was allowing them to treat Tsuna like that. She was an adult for the love of god, and allowing this offended Kaneru's sensibilities as much as seeing Tsuna's life in the manga had.

"Sawada-san, I do like robots, so long as they're not Terminators."

The little boy looked at her like he couldn't believe what he was seeing, and that right there resolved Kaneru's indecision she had been harboring on how she'd deal with everything if it had turned out to be that Namimori.

While it might be easier to let everything run according to canon, Kaneru could not turn away from Tsuna in the name of allowing things to run their course. She could not condemn a child to the future he had planned for him, and Kaneru would not.

"Tachibana-sensei? May I sit by Sawada-san?"