Maybe things are just different out in California than they are in North Carolina, but at the comic store in Asheville that Sage and I hang out at, I couldn't imagine something like this happening. Not only have I not ever seen anything remotely like blatant boob-grabbing (and we do get plenty of girls, and yeah sometimes they get hit on even if they're obviously with someone else), but on top of that I know for a fact that the owner (and probably the professional bouncer that hangs out there too) would personally boot the offender right out the door and/or call the cops if something like that DID happen.
Most people I've ever encountered wouldn't put up with something like that, and most men I've encountered have a built-in "protect women" function. I'd wager that if you'd yelled "HEY, DON'T YOU GRAB ME, YOU SICKO", this guy would have instantly been on the receiving end of plenty of unsavory attention from anyone else in the store. After all, what better way to make themselves look good to you than publicly defend your honor?
