There are definitely cases where certain 'mods' have caused political uproar, even when they are not intended as part of the game. See http://en.wikipedia.org/wiki/Hot_Coffee_mod for one example. You also discount the media storm created by DayZ and the consequences. The average journalist would never download one of the mods you mention for Skyrim (they'd be on a console most likely anyway), but there is a decent chance they would consider playing DayZ due to the recent press coverage. I think whether or not child zombies would cause a problem mostly depends on depiction and context. Nobody cared about killing BABIES in Dead Space because they could be considered necromorphs. As long as DayZ doesn't make the children too melodramatic and normal I'm not sure people would care. Beyond all this talk about child zombies, I'd MUCH prefer to see female zombies. By not including children in DayZ, you leave out a good fraction of human population, but by leaving out women, you block out 50%! Spending time creating models/animations/sounds/etc for child zombies could be better spent on literally ANY other feature.