We had the falling out problem - our bed is quite high, so we tuck pillows on either side of the mattress to minimise pain! Luckily, my two seem to be quick learners and have only fallen out once each
I don't tell very many people at all that our 4 yr old is still in our bed...made the mistake of telling a couple of friends and very quickly learnt that I should just say that he sleeps well. My Mum and Dad are a great support, as my younger brother shared their bed for many years. He's now nearly 18 and I can assure you that he is well and truly in his own space and comfortable with it!! We had got our 4 yr old into his own bed, but then our baby girl arrived and was in his former spot, so he ended up back in!