One grey area that I would like to ask the group about. If I spend 150+ nights during a year on a corporate rate legitimately, what is the impact of me using that same rate for a few weekend getaways? I have always looked on it as a perk of living on the road.

I agree that ID should be checked at sign in, and if it turns out you have no ID your reservation is canceled and you have the option of getting a room at the walk up rate if there is availability.