I've never really thought about that - I've always let my babies eat from their mums' nets, but we wean naturally, so they are nearly a year old before they stabled seperately. I suppose they could be more likely to get feet caught up, but if you use nets with small holes, it will lessen the risk.
I know ideally it's better not to use nets at all, but so long as a horse has lots of opportunity to graze from the ground, nets are economicallly preferable to messed up hay on the floor!
I get my foal next month and he will be just 6 months old, he is currently eating hay from the ground with his mum, so was wondering if i shoud give him a net. I have bought a large net with very small holes and obviously i will tie it quite high but am a little worried as have been told never to give them nets.....