There was a guy a friend brought to a game at my house who had some kind of obvious physical problem. I have no idea what the problem was--he just had kind of soft facial features, no volume control, and was very slightly twichy. Not a problem (except the volume a couple of times), he was an ok gamer and all, until about halfway through the evening, when he goes to the bathroom. I happened to need to go just after him, at which point I discovered the seat was down and there were great puddles of urine totally covering it. I mean there was piss every which place anywhere near that seat. On the rim under it, splashed onto the floor, everywhere. I can understand a motor control problem, but damn, just lift up the seat if you can't not piss all over it! What, had this problem never come up before in his life? He didn't smell bad, so presumably he didn't usually sit around in his own urine.
I wiped it up and didn't say anything. My mistake. He was invited back one more time, whereupon he did the exact same thing. No more after that.