Originally Posted by Shareholder

Free night promos are almost always per stay. It would be foolish to award them on a per night basis, even those many stays comprise just one night. Abuse would be rampant, doing what you surmised...i.e. book lots of consecutive nights at a low-cost property, check in but never physically check out, and not even stay at the property, just rack up the max number of nights required to earn the max number of free nights.