They should notify you, but I’m sure they probably do. Some sites have newsletters they email out that you can opt out of. I think they probably don’t want to bother you every time they update their terms. I assume most of the time they’re doing it because they have to legally, not because they’re trying to target their own users.
I think most of the time, gambling sites do not notify their users.
On the other hand, I'm pretty sure that it's just a rare case where even when we are not notified of the changes in the Terms and Conditions, we are still safe in our usual doings. I also think that in most cases where sites are using the Terms of Service against their users is, if the user won an insane amount and subject to investigation first even the winnings are done fair.
No choice but to comply with what they need. If they tell us some shitty reason why they shouldn't handle the win, let's fight back by exposing their name on various gambling platforms and showing the community all the proof. But I still believe there are lots of trusted sites out there that by just following what they need and being asked, will soon hand out our withdrawals smoothly.
Even if users are informed of changes in terms of service, a vast majority of users would not pay attention to it because usually, they don't include what has been changed...Just that it has been changed. So, users must re-read the document that they most likely did not read when they ticked "agree" upon signing up.
I am working on a thread that will list active, valid and unresolved complaints about TOS and non-TOS related account closures and suspensions. Hopefully this will open peoples eyes to the amount of complaints that have been submitted about a large portion of the casinos in this board.