I agree with that, if they can take the time from the beginning to read and understand the ToS then maybe there won't be a problem but even with those who understand the ToS there are some who experience problems but it is better if we can take the time to understand the casino's terms and conditions or ToS first because we should also do that which aims to minimize problems when gambling because I am sure it is very uncomfortable to have problems when we are busy gambling. Having more than two accounts in one casino can be done, if the casino does not provide more detailed requirements such as KYC which requires facial recognition of players, but for casinos that submit KYC with one of them the player must go through a facial recognition process, maybe having two accounts in one casino cannot be done.
When people read and understand the ToS, they will know what they can and can not so they will not break the ToS because that can give problem to them. They will playing gambling with carefully and don't want to spend much time in gambling as gambling is only a way to have fun in their spare time. They know that having multiple account is prohibit so they will not create more accounts because the casino will know that easily. The casino have the data of all of their members and log file from all members so from that data, the casino can investigate everything and see the connection so casino will freeze or ban the accounts. If gamblers think that having multiple accounts will help them to win, that will not be right because casino is the last winner and will takes the money from the lose gamblers.
How come having two or more account help to win more ? More accounts = more to deposit = more to lose, when chance to win is the same for every gambler. I can only understand if the situation was about users trying to cheat with welcome bonuses if there were any. But correct me if I am wrong, nobody now gives free bets or free spins just for a registration. I could understand if a person creates another account, because his first was banned, but it is a risky move, because chances for second account to be banned are increased. I can accept that someone create multiple accounts because he wants to get low level up bonuses, because wagering several thousands is always easy than, for example, wager from 50k to 100k to get free 10$. But that is also illogical. While trying to get $10, it easy to lose much more.
As @ultrloa, @Adbitco, and @Hirose UK said, having multiple accounts can benefit gamblers especially in referral. They can get more amount as the reward if they use all of their account in different time. But casino will know and will investigate it furthermore to proves that they are not cheat the casino. They will use one account and playing gambling and they don't mind to deposit more money because they have a reason why they use multiple accounts. We never know what is their reason because those people will not telling clearly the goals. For us, that will not make sense but for them, that still make sense especially if they are often doing that in the other casinos. We just don't know how and what they will do.