I wake them up if they are still sleeping at 3:30 (they go down beteen 12:30 and 1) as I find I need that timet o give them snack and take them outside to play before pick-up. I almost always have to wake someone up as I have some very good sleepers. I tell parents if their child's sleep was less or more than usual, but leave out exact times in general. However, they do know that I wake them up by 3:30 if they are still sleeping. If they do sleep past this time (rarely it happens that they went to sleep late and I want to let them sleep...usually on a Friday) then I do tell parents so they know not to push an early bedtime.