someone who makes a sizeable portion of the membership uncomfortable because they are constantly trying to crack on to them. And not taking no for an answer. Again and again.

This. A thousand times this. One person carried around massage oil in their pocket, then started massaging unsuspecting con-goers. They are dangerous, yet they're still allowed to go to cons.

I would rather be in a room full of unruly kids than a room full of well-behaved adults and this person in there.

Children are the least of the problem at a lot of these cons.