In the rumors, there were three levels of troublemakers.
If you happened to do something bad, you were sent before Firelord Zuko. When you came back, you could never remember what you had done wrong. Everyone who'd been forced to pay Firelord Zuko a visit would always come back believing in him fully.
If you were sent to Firelord Zuko, you were brainwashed.
If you somehow managed to return back to rebellion after your brainwashing, you were sent before Lady Katara. Everyone who was sent to Lady Katara would come back twitching, like their veins were being pulled by invisible strings. They warned of horror stories—of how if you put up a fight, your body turned against you at her will. It was brainwashing, but with pain as the incentive to change. And you always wanted to change, if only to be rid of the suffering.
If you were sent to Lady Katara, you were tortured.
If after all this you still had the guts, nay, the stupidity to continue turning against the government, you were sent before Avatar Aang.
No one was really sure what Avatar Aang did to you, as very few people had been radical enough to be put under his care…and even fewer of that number had returned. But of those that did, all had one thing in common: after seeing Avatar Aang, none ever spoke again. Of revolution, of how they'd been tortured, of their sentences, of what Avatar Aang even looked like. After their session, not one word escaped their throats.
Like the very air had been sucked out of them.
If you were sent to Avatar Aang, you lost everything—including your will to fight.
But they were only rumors…weren't they?
Everyone was afraid to find out the answer to that question. So Firelord Zuko and Lady Katara and Avatar Aang didn't have to waste much time dealing with troublemakers.