Here is some simple math for you socrates:
The sponsor should know the average value of a signup (including rebills and upsells, cross-sells, etc...)
If they know for every signup it averages out to $60 for them, then they can offer say $40 PPS and do fine. No need for anything shady.
You can pick out individual cases where they lose out on one affiliate whose members don't rebill as well, but you can also point out where an affiliate sends traffic that rebills at an above average rate. In the end it will all average out (fradulent affiliates being a different issue).
