I don't think casinos will give consideration regardless of who you sign up with, you have no protection if you sign up for famous streamers or one of their VIP, affiliates are term based, if they find your account violating any of their terms they will ban you and confiscate you, if you have a big number of referrals do all you can to make your account clean so you continue to reap rewards of your effort of recruiting your referrals, and casino don't care if you have hundreds of referrals, you will not get VIP status as a super referral, in fact they change their affiliate terms for their referrals to lose their earnings, so be very careful on the kind of casino you're promoting.
You're correct, just like what we know centralization controls everything: their sites, their rules.
They can change whatever the terms or programs they want without need to notify the customers, it's really sad if someone suffer in that situation when they already have a big number of referrals. All he can do is report the casino and post the proof, unfortunately he might not archive the old terms or programs.