I’ve done it in races. I’m not proving anything to anybody by doing it. I may not be a threat to the podium, but it seems silly to bust your ass for months at a time and spend tons of time, money, and energy to get every last watt available before the race shooting for the best time possible, and then casually stroll into a port-a-potty and take a piss and throw it all away.
It’s not easy to do on the bike. Especially when you’re still pedaling and trying to keep a decent pace up. Then it starts to hurt because you just CAN’T go. But once you break the seal and it starts to go, it’s really an amazing feeling. And I’m glad to do it while still on the course instead of holding my junk on the side of the road and looking over my shoulder at everyone passing me.