Have you ever met a stranger for sex?

Count me in on the missing fourth option. No way!!!

I would suggest that if she is going to do it, tell her that you care for her enough that you want to know exactly where she's meeting him and for her to check in with you multiple time so you know if she's okay or if the police need to be called.

I could never do that. Unless the 'stranger' was a friend of a friend or something, no way. Even the idea of hooking up with some random at a bar is unsettling to me.

I have, however, met people online in person before (not for sex). We met in a public place and had people we knew with us, and it went really well.

Nooo way, never.