I took my youngest to a messy play class for the first time today. It was from age 6 months - 2 years. When we were getting cleaned up at the end, I noticed that several of the little ones were wearing swim nappies 
There was no water at the session but there were wet textures like custard and spaghetti. Obviously a lot of the babies are putting these in their mouth, so surely it's totally grim for them to also be in swim nappies in them on the basis there's likely pee in there too?!