In my example, after modifying the reservation a few times by walking, they wouldn't be able to change all of the guest names anymore. If the required guest would not be there to physically check in, then they would have to cancel the reservation. They could still add or change family and friends, but they would have to be there as well. So it would actually account for that.
I doubt there's a way for them to 100% boot out of all of the "commercial" renters because there will still be some that use some of their points but still rent a lot and toe the line. I think it would still be nice if there was a way to keep people in those situations from constantly walking to popular dates just to secure renters. My example would still add additional benefit even if they start rooting out the low hanging fruit of huge contracts that rent out all of their points each year. And actual members can still rent, just not after walking the date more than a week or two