This is a quick random thought, but I had wanted to mention it before and had forgotten.
Argentines show some seriously non-kid-friendly movies on buses. The most obvious example of this was Mel Gibson´s Apocalypto, which is so bloody that it makes "Saving Private Ryan" look like "Heidi." There are no volume controls, and there´s basically no way of keeping a child´s eyes off of the TV outside of trying to distract him. On a somewhat related note, watching a movie in Mayan with Spanish subtitles was a new one for me. Fortunately, you don´t have to be Cervantes to follow the movie, since it relies much more on visual imagery than on dialogue.
Some of the other movies they´ve shown have been pretty questionable as well or general audiences, although in fairness, at least language isn´t a problem for the kids, since most of the movies are in English with Spanish subtitles.