When I was little (1st grade) we had a substitute that told us that. The school down the road from us had another teacher - same day - that did the same exact thing. Both were Muslim, so they didn't believe in Christmas at all. They had planned it out to tell the little kids that there wasn't a Santa. But I remember that she read us a story and then she said "There isn't any such thing as Santa Claus, your parents just put all your presents under the tree."

My mom was sooo mad, she called and complained, and got the sub fired (her first day of subbing, too). The other one was fired as well. So, I knew from an early age that there wasn't a Santa, but my parent's still joke around that Santa's going to bring the gifts. (and im 15!)