It could be like as simple as "having multiple accounts", some do allow it, some do not and if you just don't because of common sense, that will result you with going to place you know that has multi accounting allowed, without even checking. So you should check and see if they allow it or not. If you do not check and do it and that's not allowed? You could get all of your money frozen.
With this logic, Since you already know that some Casino doesn't allow multiple account, By using common sense logic, You will not do it in all the Casino since you know at the back of your mind that multiple account is forbidden in some places if ever you will not read the ToS fully. Why would you use multiple accounts too if you have one working account? There's a forgot password to recover the account. This example might be not appropriate on this kind of argument since the common reason why user want to use multiple account is to abused faucet or an active promotion.
You should act safely and limit your Casino activity if you will not read the ToS and just want to casually play inside.