I'm sure I am a bit paranoid about the abduction thing. I know the facts like you said about it being more often family/friends that do the abducting but it's just one of those things that worries me as a parent. I'm not perfect so if I have to be paranoid about something I'm sure there are worse things out there to be worried about.
Also, exactly like you were describing, I don't want to be one of the parents who lets their kids run wild in public. That is a pet peeve of mine when I am shopping or something and kids are running around and being crazy and getting in the way of other people. I always think "Where are their parents and why aren't they stopping this?" There are places (like playgrounds) for kids to act like that and places (like a library or store) where kids need to learn how to act.
And I agree, a lot of people have the whole thing completely backwards. I think it would make a big difference if we started holding more parents accountable for the things that their children do.