I haven't read all 148 pages, but what did the other rental companies do?
They way I see it, there is no good solution.
Option 1) owner gives money back to renter. Owner's points expire. Owner is pissed.
Option 2) owner keeps 70% then David gives additional 30% on check in date. Renter is pissed.
3) owner keeps 100%, and David gives renter back 100%. David (as the middle man), ends up covering the entire cost. Customers are happy. David takes a massive loss. (Even a company as large as Disney would never do this. Disney wasn't exactly giving out free hotel rooms to those
DVC members who's points expired. Their solution was to take inventory away from those who's points didn't expire).
4) Do what he's doing. Owner keeps 70%. Renter gets a 100% credit. David keeps 30%. It's not perfect for anyone. David is still taking a loss. He's using the 30% to offset the 100% credits. Of course, some won't get used, and he's spreading the negative cash flow over a longer period of time.
None of the solutions are good. I don't think its as simple as just letting owner and renter hash things out for a multitude of reasons such as.
1) privacy laws.
2) giving customers the opportunity to gain confidence that they won't need his service in the future. Etc....