Cool idea, Stephanie! I went swimming in my brother's pool yesterday and had no problems with the wafer holding its seal. It was the first time I had gone swimming just a few hours after putting on a new wafer, so I wasn't sure if it was going to hold, but it did. I brought a wafer change, just in case, and was glad I didn't have to use it.
Our pool installation is coming along swimmingly. My husband and I promised each other that we wouldn't pee while in it, but I said I couldn't promise that I wouldn't poo while in it.