you can't punish a child in child care, how would you like it if someone was punishing your children???
i understand why you are upset at the situation but look at it from the flip side, if they are allowed to punish that behaviour at day care, are they allowed to punish your child for snatching a toy from someone or throwing a tantrum????
Umm yes you can! I worked in all child care areas, centre, OSHC and FDC and each had a 'naughty spot/time out' rule.

I would hope that if my child was hurting other kids he would get punished! At the FDC they are at, if they misbehave they go on the naughty step.

At home I disiplin them for things, and I would hope that they weren't let to run amok when they are elsewhere. If they snatch toys, they go in the corner, if they throw a tantrum, they get left to scream it out, or they go in the corner.

They don't do these things usually, and have thrown very few tantrums in their lives (I can count on my hand!) and it is all because... they got ignored or went in the corner.

Let these behaviours go, and you will end up with problems lasting far longer then a couple of weeks until they learn that it's not ok to walk up and snatch a toy or bite someone. And 3 years old is DEFINITLY old enough to know better... I would be horrified to find my 3 year old still biting or snatching.