The number of affiliates that left players unpayed is in the industry average of crooks(chargebacks and other scams).
I am not sure if many people know but over 75%(and i believe more) of rake back market is based on Party skins offering rake back. There it started and as in many other businesses everyone folow the leader. If Party, Prima and Crypto agree to stop it it will either dissapear either a small room will try to get all the rake back action.