I think for guys it depends. I would guess the guys who say they're OK with being groped would only be OK with it in certain situations, as you implied.
I've found that to be the case for women too. But then it isn't groping...it's the scenario of where you are suddenly and instantly attracted to that mysterious and delicious stranger across the room, and hope that they're attracted to you too.
As for fantasies, I get the impression a whole lot of people have fantasies they wouldn't want to actually play out in real life. I know I do.
Agreed.