You know most casinos or betting site highly frown that and if they noticed that one IP is tied to multiple accounts they would dig to suspend your winnings and or would freeze the account because an investigation was carried and the account was originally created by one person at this point they would term it to be cheating with multiple accounts, main while where you were making deposit your account wasn't tied to any multiple accounts because there is a winning which they wouldn't afford to lose from there side and will search everything possible to make sure there is an error and to corrupt your winnings.
Casino will investigate everything related to the accounts and yes, they can freeze the accounts and if gamblers proven doing something that break the ToS, casino will ban and close the accounts.
Casino will tell to that gambler that they are cheating the casino with multiple accounts and the casino will take the money or will give the deposit money and close the account. In this point, gamblers should understand that they don't have to cheat the casino because casino will know about that. We must be careful from breaking the ToS so we can playing gambling without have a problem and we can enjoy our time in casino.
What we are driving here is about using same IP to create account, what happened is that there are some home that uses same IP or same network within just a specific area or village, since this people are known to be using IP and they are linked as one account where as they are not what would you do.
I think here is where the problems lays because if one person definitely secure winning all the accounts would be fished out as one person trying to cheat the casino therefore he or she would be restricted and blocked withdrawal and at some point most casino doesn't refund deposited fund to the gambler.