I think it's a reasonable policy. They have the same policy at DD's kindy, but that kindy is for 4-5 year olds only so I think it's just an expectation that by that age your child will be TT. Having said that though, they accept that accidents do happen even at that age and they deal with it - they don't expect the parents to come in. They ask that you always pack a change of clothes and undies for that reason, and even if you happen to forget, they have a box full of spare clothes that they will dress your child in if need be. It's handy also because the children do a lot of messy play - water, mud etc so they sometimes need a fresh set of clothes.

Like others have said, I would put him on the waitlist and see what happens re TT - you might be surprised how quickly he picks it up. I know my friend was despairing of her DS ever TT, but within a week of his 3rd birthday he was out of nappies and now even takes himself to the toilet if he needs to!