Maybe I am a rude bitch, and my social skills are awkward as hell, but if I were in a bar minding my own business and a random guy offered to buy me a drink, I *would* probably ignore him. At most, I would say "Please leave me alone."
On the other hand, I don't drink, and I don't go to bars unless it's a get-together with a group of friends, mainly because I *don't* want to deal with random men talking to me. Because unfortunately, it's impossible to tell who's a nice guy who'll take no for an answer, and who might be lurking around waiting for you outside the bar because they're going to get what they're after no matter what.
My responses in this thread, and the way I look at situations like that, are unquestionably colored by trauma in my past, but I know other women who have the same fears and feel the same way even if they haven't had the same experiences I have.
In the situation where the guy threatened to track me down and go after my daughters, I didn't contact the police because his profile gave no indication as to his location and because real names aren't available on there so all I could have said was "SuckMyDick2000 on AdultFriendFinder said he's going to come after my daughters." Aside from not having the necessary information for a police report, there's also the stigma surrounding *being* on sites like that in the first place, especially for women in some cases; the police might have been just as likely to say "What do you expect if you're hanging out on a dating site" as to take the threat seriously.