That's the main reason why casinos don't allow creation of multiple accounts. Although, if it works for someone then its okay but for ones safety it's always better to avoid creating multiple accounts at a casino. Personally, I avoid creating multiple accounts and I also save my account credentials on paper as well as a text document so I never forget about it.
It’s better to avoid it because, even if you claim you’re not using the other account, the fact that the system detects a link between two accounts could be used against you, especially with shady casinos. Legit and reputable casinos are less likely to pull something like that, but it’s always better to be safe than sorry, right?