I am going to chime in one more time. (Ugh! I must be nuts to keep posting on this thread)
Keep in mind I do not know a lot about Wyndham. But- here goes-
Even if she booked a back-up, as you suggested is a possibility; when she booked the backup one now, how then did she get the exact unit for that reservation if the original booked unit was already booked for that same unit?
I am thinking she did not have a backup since i am in the same unit as originally confirmed.
Again, I am just interested for knowledge sake.
She never needed the back up if she had one and was able to get yours discounted. It can be very easy or like others have said a nightmare. A lot depends on the skill and knowledge of the owner. I would not be comfortable with most people doing it as the risk would be to high.