Hold on. There is a legitimate reason for this and it has happend to me, but not at SPG properties.

I fly to Shanghai for 5 nights on business and am booked at the Westin. When I arrive, I am notified that I need to fly up to Beijing for a night for an important meeting, then fly back. I book the St. Regis. Not wanting to clean out the Westin and haul all my stuff to Beijing just for an overnight meeting, I just don't check out of the Westin and pay for the night there as well as at the St. Regis. I paid for both nights, I should get credit.