Although I do allow Minstrel on the bed and have done so since I got him (with supervision obviously so he cannot jump/fall off) - he would be turfed off smartish if I found he was peeing on it...or worse. In the daytime I shut the door, but now it is getting cooler at nights I put the gate up to allow warm air to circulate, without allowing him access when I am not in the room.
HBP has good point about texture, If I put an old towel or matting etc on my tiled floors (kitchen, hall, bathroom) - it is most likely Minstrel will pee on them if in hurry, however he does not seem to like bare cold floors so will ask to go out.