Good grief! That's terrible that teachers would let the students totally wreck those school uniforms like that!!! You must be beside yourself with fury! I've worked in an Early Learning Centre where we were highly conscious of potential damage that could be done to clothing and did our best to help the kids avoid it. Smocks were compulsory for a start. We would use products like Crayola that wouldn't stain too. Our daughter also goes to a private school where they also have to wear smocks. I know how tricky it can be to supervise children during art but all teachers should be aware of the cost to parents and (whether private or public) teach children to respect clothing. I hope you provided the teacher in charge that day with some "feed-back" regarding those destroyed uniforms so that awareness is raised.