Rated 'R' for a reason

Why do parents bring their kids to rated 'R' movies? It must be the way I was raised but this really bothers me. Last weekend I went to see Cop Out with my boyfriend and when we walked in there were at least 4 kids under the age of 12 there. There were all with their parents but in my head I was wondering why the parents would do that. No babysitter? Then chose a movie your child can see. Cop Out wasn't as bad as other 'R' rated movies but it was still not for young ears. The f-bomb was every other word and people getting shot. There was no sex which is a plus but there was lots of sexual references. I know what you are thinking, I am lame because I think about these things but you have to be a certain age to see these movies for a reason. But here is my new question, what about Red Box movies? Any one can rent a rated 'R' film there so why not take them to see it on the big screen? I shouldn't be so bothered by this but I have been to a lot of 'R' movies where there are kids. It creates an awkward situation for those sitting around the kid. I know they don't understand most of it but why pay for them to sit and not understand. That's just awkward questions to ask later. Parents need to think before they allow their child to view whatever they want to. I understand that I am not a parent but in my house my parents made it clear what I could and could not watch. It's rated 'R' for a reason parents.