This subject is covered about every three days or so my friend. I recommend you do a search on the posts here using your keyword "Security" and you will find many posts and comments on the subject.

Good Luck

unless you are doing something obviously illegal (do you or your companion look like a terrorist?) or either of you have been banned from the property, security really doesn't care.  They want to make sure that one of you is staying there and belongs on the guest floors.  Just don't sing in front of them something to the effect of "I'm gonna screw this whore six ways to sunday...".  I don't think your companion or the guards will think very highly of you (and they still might let you go if you flash your room key).

Without the room key, the guard will call your room and ask if the person is allowed to come up.   Losing the key means you go back to the front desk and try and get a new one (if you still have photo ID, not a good way of starting off some private time).

Yawn,
 Bob