This kid is probably never allowed to get messy at home at all! The mom doesn't seem to understand that letting kids play and explore and allowing a bit of dirt or mess sometimes, especially outside, is a good thing!

I have it in my contract that parents must send their child in "play" clothes, because messes, stains, accidents, etc happen and we are outside every day that we can. If mom doesn't think that's good enough, what about you or mom just going to the dollar store or value village and buying an outfit or 2 for a couple bucks? Kid arrives, you change them, let them play, change them back before pickup.