First off, that scene isn’t so they don’t recognize their faces. It’s to look like spirits and scare/shock them. They were a small army trying to use crazy tactics, I don’t see what’s so wrong about that. I’ve read it multiple times and I don’t remember a point where they go topless implying no one would ever look at their face if they were topless.

As for the author, I don’t know much about him, but I like the books. And way I think Michael Jackson is a bad person but I can still enjoy his music.