A shame we have to embarrass parents into paying isn't it but we do what we have to do. I have done the same thing with supplies such as putting up a sign saying all children need: sunhats, sunscreen, extra shorts and then list all of the names. I then cross them out as the supplies come. That way the parent only has themselves to blame if they are the last one and find it embarrassing. It works because no one wants to be last, lol.