It sounds like there are a lot of problem people with these online dating sites. I noticed they also tend to hang out at bars/clubs too. They tend to look for easy routes when it comes to meeting others.

I think it's better to look in a more community type environment. These bars and dating sites are not "community" environments and a person is more apt to get singled out as you have mentioned where it's just you and that person. This sets the atmosphere of being singled out right off the bat without seeing how the person interacts in a more community type atmosphere. You are more apt to get a loner looking for someone they can isolate and control.