This thread is an example of why it is important to check with a program if you plan to publish any offer that is not standard and presented in the aff site.
It has little to do with 888 in particular, this would happen to you anyplace.
For unique offers, you first need to obtain permission under any circumstances, and secondly you need to arrive at a unique payment plan tailored to that particular offer.
All offers are based on calculations that ensure everyone can still make a profit, and it is still attractive to the player. Designing these offers is not an easy task and the affiliate can’t just go around making up their own unique offers without the proper calculations in effect.
That said, most programs will be happy to work with you on such offers.