I'd just like to add - I think bluetooth is great.
I only activate it to use with my earpiece when driving in case of an urgent call, but the technology is superb.
As for kids - well if you need to give them a mobile - ensure it does not have bluetooth or even a camera of which there are plenty - and therefore no problem. Neither of my children will be getting a phone until they are well into their teens.
Probably not helpful, but hey.
Duncs