I don't know, I don't think I could do it. There's something horrifyingly wrong about peeing on oneself. I feel the same way about not wearing underwear. I remember a time when I was about 7 and my family was on vacation. We stopped by a neighboring hotel and went swimming at night. We didn't have swimsuits so my sister and I just wore our undies. Afterwards, in the changing rooms, I went to put my clothes back on and my mom said I had to take my underwear off because they were wet and it would make me too cold walking back to the hotel. I tried to refuse and basically freaked out. I felt panicked and started screaming and crying. Not so much in a tantrum way but more in a frightened way. My mom wouldn't let me have them and so I had to put my clothes on with no underwear and it was the most sickening feeling in the world. That walk back to the hotel was awful. It felt so wrong and it makes me feel creepy just thinking about it now.
Anyway, that's much the same way I feel about peeing on myself. I don't think I could willingly do it for any amount of money.
Not to mention there's cameras around, so I'm sure that wouldn't help matters.