Why should this be the case? There have been several times where I'm staying in a city for an extended time and then visit a smaller outlying area. Rather than check out of my primary hotel, I'll just pack a small overnight bag and head out for one or two nights and then return. This was never an issue with SPG before and in fact would get points/nights/stay credit for both properties. Why is this grounds for program termination at Marriott and where in the T&Cs is this detailed?