Parental Control
Touch screens are a great concept, but they never seem to work properly anyway! I travel regularily with 3 kids under 8. I make sure that they don't fiddle with the screens or kick the seat in front (well, at least more than once!). We got split up recently on a long haul flight and my 7 year old had to sit between 2 guys in economy. Cabin crew member was worried as they shouldn't sit a child next to a guy (airlines obviously think we are all like Mr Glitter...). My son insisted he stayed where he was. Both guys couldn't believe how well behaved he was for the entire 10 hour flight. Just sat quietly, ate his meal, said thank you and watched a couple of kids films (I hope). It's all in the parenting. It might seem over the top, but there's plenty of time to be a 'kid' when they are at home.
Shame the kid banging your seat wasn't sat behind my kids. It would have looked great having my 3 year old turn round and tell them to sit still and behave....