My son's day care indicates on a board what meals each child has eaten during the day. I've observed that many children don't eat the snacks and some children eat three serves at lunch time.
So just because it's in their schedule doesn't mean your child will be eating every time there is food offered. Each child is different.
It's important for development that children aren't left hungry so the day care center is just being responsible by offering snacks; and lets be honest, we're talking about slices of apple and dry biscuits, not chocolates and ice-creams.
Also these snack times are used as a reminder to staff to ensure children are stopping play to have extra fluids, wash their hands to prevent nasties like cold and flu spreading and reminders to take a toilet break for those who are toilet training.
So if your child doesn't eat regularly in between meals at home there is a chance they're also not doing it at child care. If he has enough food to eat at school and he's not asking for food at home then I wouldn't worry about it. Sounds like he's just being well looked after.