Toilets on Paxo's beaches are few and far between and so I'm sure lots of people probably do wee in the sea! I prefer not to think about it. Especially when snorkelling!!
We never stay all day on a beach and I find that due to the heat and even though I drink lots of water to compensate I can manage till I get to a loo without too much discomfort. . But I do remember one year in Thailand. I had a water infection and we were being taken by car via the middle of nowhere to a beach. I was in agony! Asking to stop the car and go in the bush was not an option. Bare bum. Snakes. Definitely not! Needless to say by the time the car arrived at the beach ( no toilets) I was out and running for the sea as if my bum was on fire. Anyone watching would have guessed by the blissful look on my face what I had done. Did I care at the time? No. Sometimes needs must!