Unfortunately, I have found a couple times that there needn't be a ledge in the way for the toilet seats not to stay upright. Perhaps a word with the seat manufacturers is in order. (This is of course not a phenomenon limited to hotels.) The easiest solution to such a defective seat is not mentioned in your list, and that is to sit down on the thing. I mean you're in the room by yourself, right? In the bathroom by yourself, at least, I should think, most of the time anyway when you're working that sort of function. Nothing to prove, no testosterone battle to lose, no one will ever know except those people watching the hidden cameras.