Back in the '80s, a friend of mine had a seat in a Consulier (look that one up) at the Nelson Longest Day. One of his co-drivers radioed in that he needed to pit, 'cause he had to go and was pointed told by the team manager to "shut up, piss in the seat, and keep driving." It wasn't Steve's car so he didn't care but it was an insight into a mindset.
My fave is the story of Gianpiero Moretti pooping his drawers rather than coming in, when he won Daytona with Mad Max. But then, you see little old Italian ladies peeing by the Autostrada: They just don't have the potty taboos that 'mericans do. Blame it on the stand-up, "bombsight" toilets" that they have over there...
I did the NASA 3.5 hour enduro at VIR solo this spring and it was really fine in that respect. I had a drink bottle and emptied it, having started pretty hydrated, so the water went somewhere. Some of it went into the seat but not through me: I let the hose dangle between my leg and the bolster of my Recaro, and squeezed the bite valve enough that I suffered from some embarassing wetness.
K
EDIT - Geez, what a highjack.