I don't think anyone here is referring to people who are unintentionally in the background of someone's pictures. We're talking about intentional acts.
For those of you who think that photobombing is OK because YOU think it's fun...how do you feel about the singing/chanting tour groups? I have to assume you love them all...after all, it's just kids having a good time at Disney, right?
or inappropriate displays of affection, or dropping the F word non stop in front of your kids, or telling your kids in line for the characters that they are just college kids in costumes? or walking up and standing in front of your kid just as a parade starts?
that is just fun to them, it's OK with you right?
no one form of rudeness is any more appropriate than the other just because YOU think it is fun. contrary to your parents and the schools today YOU aren't the center of the universe.