Many of the replies here and suggest to read the ToS first, but dont forget that the ToS could change anytime and they have the rights to update it anytime they want.
Most of the ToS on any casinos are almost the same, but not with their reputation, so Reputation is the most important thing we must check first before we start playing on any casino.
ToS can change at any time, but many casinos will notify all their members that there have been changes to their ToS, so all members need to check their ToS again. The casino will notify changes to its ToS via email or there is a notification window that will appear every time its members log in to their gambling account. That will make it easier for members to quickly find out about the changes and read the new rules. Usually, trusted casinos do this because they want to avoid doing something that could impact their reputation, so they will really provide good service to their customers.
You are right that almost all reputable casinos always notify all their customers of changes to Tos content.
And there, when customers log in to the site, there is notification to agree to all the contents of the Tos, but the gamblers are reluctant to read all the contents of the Tos changes and immediately click to agree to the changes.
However, in the end several problems occurred and in the end they blamed the casino which seemed to be at fault in the case that was happening.
Incidents like this happen often and are truly very unfortunate.
I prefer sites that do no hide anything which most of them does. Such as KYC related problems. Whenever a user try to withdraw a higher amount this occurs. Also gambling sites which doesn't have good customer support or reputation should be avoided. I used to gamble to those sites that supported many games as I feel bored pretty fast.
Use site with good reputation and high trust from gamblers, plus site that already has very large community so you can be sure that there are no hidden rules or regulations.
Sites like this will write down all their regulations in detail, even including KYC, they will clearly state what may require KYC and most sites state that there are indeed KYC requirements if necessary.
From this it can be concluded that every customer only needs to be prepared or prepare KYC if the site they use asks for it.