I've been using this technique for a few days since I saw it in a youtube video. I mostly use it for the final pass on my neck to get those stubborn hairs. I have not cut myself doing it more than a very little nick, but am very careful.

I did nick myself pretty good in an ATG pass coming across the jawline coming up from the neck over the jaw this morning. Don't think I'll try that one again, too many angles to ocntend with.