I would agree that it’s “double dipping” IF the points are returned to the owner in the same condition that they were in at the time that they were rented. Unfortunately, that’s not always the case.
I got “lucky” compared to other owners. My “renter” is my niece and her husband. They were due to arrive in the middle of May. I contacted her at the beginning of April and then again last week to encourage her to reschedule. I have a September use year and some of those were 2019 points which needed to be banked by 4/30., Some were borrowed from 2020 and
DVC put them back into the 2020 use year. Only 2 were banked in from 2018 (I’ll be losing those on Aug 31). I was able to re-book her for November, although not in her original resort and accommodations.
I would have done the same for some who rented directly from me, but I might not have refunded the cost of the 2 points that I lost.
Now consider that instead of this being my niece, let’s pretend that this was a rental thru David’s. I would not have been able to contact the renter to see if they wanted to reschedule their trip. I would not have been able to cancel the reservation. I would have had to wait until Disney canceled it in May. At that point, I would have been past my banking deadline and those points would be toast as of August 31. The borrowed points would have gone back into the 2020 use year according to what DVC is currently doing. And the two banked points would still be lost. So, out of the “returned” points, fewer than half would actually be usable at full value for a future reservation and the remainder would be severely “distressed” and virtually un-rentable before they expire. Would it be “double-dipping” if I didn’t return what David’s had paid me up to this point if more than half of those points are useless due to David’s unwillingness to do their job as an intermediary and work with both the renter and myself to reschedule?