Maybe not for a single affiliate, but in a community like this, people would talk, and it would eventually come to the fore.
An example would be the continued good customer service offered by 32 RED Casino. A single player would notch it down as a nice experience, as it should be. But because they offered it continually to ALL customers, it became a talking point in a community (Meister), and it got elevated to levels far beyond what a single satisfied customer could provide. Players were happy because they were advised by a community on a reputable place to play, and 32Red were happy because they got many new customers in this way, by just doing their job right.
A lot of affiliates are very vigilant about their business. If someone was cheating outright, it would be brought up here, I’m sure.