I'm not sure what I would have done at the scene. I would have first thought a burglary was in process and, seeing a hotel security guard in on it, I would have probably just gotten the hell out of there and called the police once I was out of the building. I doubt I would have whipped out my cell phone and called 911 on the spot - unless I was already cornered in the room and the guard was armed.

In any case: that's downright effin' creepy and totally wrong. At this point, I'd definitely be giving Marriott a serious earful.