Personally I don't feel I need it. I'm confident about my ability to assess people. Yeah it may take more than one time to realize that x or y aren't my type of players, or that I don't get along with them, or our gaming styles are incompatible... Not a big deal. RPG is a social activity, it means spending time dealing with people, fine by me. Plus someone's devil could become my best buddy, that's really subjective.
Now if you meant more like a WARNING button that would pop up some incident report form, in case say you met a real whacky guy that owned pedophile material or was a terrorist proselyte, that's another story. It could be important for you to have this minimum level of protection so PnPG isn't an easy target in some hypothetical future for some maniac lawyer trying to throw some blame on the website...
Au gibet noir, manchot aimable, dansent, dansent les paladins
Les maigres paladins du diable les squelettes de Saladins.