If kids walk around in a theater, blame the parents for not knowing what their kids are capable of. In my opinion, a 3 year old has no business being in a theater, watching a 90minute movie, it's just too much to ask for him/her to concentrate and be calm.
Try it again at the age of 5 or 6, but I think Germany has a completely different menatality in that case.
And I also never had a bad experience when I went to the movies with my niece and nephew, but again, Germans are usually pretty calm, while american audience, at least I heared that many times, is a little bit more outgoing, so like the parents I guess.