4. I allow players to open accounts as affiliates, and claim the great new 25% “rebate” on their losses. It works so well as a retention tool, that I actually encourage it, and tell players to open new accounts on their own tags as opposed to the hardworking affiliate that initially sent them (or, of course, word just gets around naturally about this great new “bonus”.)
Now you are making things up. That’s cheating the affiliates from their money, it has nothing to do with players opening aff accounts. That’s why there are cookies we use for tracking and some affilites regularly check to see if the programs don’t cheat them by switching players to “corporate” accounts. Also, I as an affiliate would never encourage players to start their own aff account, since that’s the exact oposite of what my affiliate business model is 
Those 3-4K players who think they are clever enough to open their own aff account (without being taged with a cookie from an affiliate first) – more power to them.
PLus, there are a lot of sportsbooks who offer as much as 100% cashback on losses on certain bets, some even offer percentage of your losses every month as a cashback. It seems you are way behind the whole “cashback” thing. Even if you offered 50% cashback every month, you will still need the affiliates, even more so than with 0 cashback.
I as an affiliate don’t feel threatened by a handful of guys who decide to open their aff accounts. If they do so at a sportsbook to where I have refered them – they are already my players, no matter how many aff accounts they open. If it’s at a different sportsbook – I don’t lose anything. Don’t forget that a lot of affiliates started as players, so a long-term profit is also possible. I know I played online casinos long before I became an affiliate…
It’s a slippery slope, which like I said, is in nobody’s interest
The few online casinos and sportsbooks I play at would beg to differ with you on this one I know gambling some of my aff earnings is not in my interested, but the casino sees it in a very different light.