Well Fitzpatrick would probably use the same handwave for Patch that Meyer does - he's so ridiculously overpowered that there's no laws that can hold him to a punishment. Spoilers, but humans can't see him unless he wants them to. He's fast and powerful and we know he can mindrape. The only ones powerful enough to take him are other angels, and clearly they don't care because they are letting him run around doing whatever he wants. >_<

I also suspect that Fitzpatrick is as sheltered as Meyer is. That would account for her idiocy about Patch, to be sure.