And if found that the user didn't take advantage of promotional offer, but still guilty of having multiple accounts, you still have the right to stop withdraw because the ToS for multi-accounting is not followed.
You have to tick "I agree with ToS" on registration, which means you agree that you will follow ToS and you won't brake rules.
So, when they say multi accounts are against rules and you may have only one account I am pretty sure it means it is against rules and you can have only one account.