I will also add another +1 to the comments here.

As someone who stays 125-150 hotel nights a year. I virtually always have my inside bolt latched when I am inside the room (98%) unless i'm just going running in and going back out, or occassionally stressed to the point it slips my mind. Was going to make the same comment in the Alex Trabek thread - that it would never happen to me because no one can get into my room while I am asleep - short of breaking down the door.

Thusly I've never had someone walk in on me - though I have definitely heard people try the door. I had an experience a few months ago - i went to the door. Slid the key, got the green light, but the door was bolted. Expected someone to yell or something - but nothing. Went back and they said for sure no one is in that room. Somehow the door latch had engaged with no one inside the room. Maybe a heavy slam engaged it? The maintanence guy had to come and pop the latch, and re-set it.