I used to ignore other people's rudeness, but I find that I have a lower tolerance for it now that I have a kid. I've taken to actually confronting people by firmly saying, "Excuse me, but we were in line and you cut us," or whatever the offense was. People will usually stop their behavior if they are called out on it. (I only do this if I'm directly affected though. It's not my job to enforce Disney's rules).
Of course, some people become incensed if you dare question their behavior, so you need to be prepared for that if you're going to actually call people out.