I was always terrified about it.
I knew they were brothers. That knowledge alone was very, very dangerous. I couldn't in a thousand years count how many of their enemies would be absolutely delighted to find that out.
Then there was the fact that they were actually living together.
I couldn't count how many times I almost let it slip. In some ways, letting that one out was just as bad. Any little thing I said could make someone realize Harry was living with a White Court vampire, and without explanation they would assume the obvious.
Damn.
Keeping secrets sucks.