I think the majority of the gamblers out there when they think about the very first thing they want to do when they finalize the process of creating an account at a new casino, do not consider reading a legal document regarding their responsibilities toward the casino as being at the top of their list.
Still it is important to do so, because as you mention there are casinos out there which are looking to aggressively use their TOS against their clients as a way to rob them.
Yes, it is their fault that they did not read the documents or regulations in the casino. That could cause problems for them, especially if they were to win a big win. They will find it difficult to comply with the regulations and require further verification. And those who don't agree think the casino is cheating them by adding those rules to their TOS even though those rules were there long ago before they registered. But if it is a shady casino, there is a TOS or no TOS, the casino will cheat its users so we shouldn't be surprised when we hear that there are people who cannot verify at a shady casino.
In a shady casino where those cheat is possible to happened, they are not putting the business for long term but just to open it and try to suck money out from gamblers who wanted to take advantage of their offers, but it is different from established casinos where they have those TOS before you sign up and it's more on your fault if you missed reading all the details with the terms and conditions.
More on people who take time to read and know what are the rules behind those offers. They are more into knowing the grounds and
not just taking the offer, as they understand that there's always something behind.