Yep, it happens. Lil Buddy has been pushed over and biten and scratched. But then he's pushed over, stolen toys, kicked and screamed at the other kids too.
In fact, at home, we have the same problem. I can be sitting RIGHT NEXT TO THEM while they are playing quite nicely with one another and suddenly something happens and someone is hit or bitten. Does that mean I wasn't watching closely enough? Nah, just that kids do stuff you don't expect sometimes.
And honestly, I bet Aidan has learned to take things from other kids. I know that as mom, you want to think your son is perfect and would never ever do anything wrong, but the fact is that kids do that. They will learn to share, but no 2 year old is perfect at sharing. So don't doubt that the daycare workers are telling the truth. They will tell you what happened as they see it (if they didn't want to, they'd have not told you about the bite).
One day you'll be the mom going in to be told that Aidan smacked another kids with a block or something.
LOL... I'd ALWAYS rather my kid be on the receiving end of something like that (as long as they don't get seriously injured of course) because it makes me feel like a horrible mom when I'm told I had the "bad" kid that day.
LOL.