They let one user with multiple accounts win and after they win they often confiscate their winnings.
Unless someone use same IP address, there is no way that they could know if someone is using multiple accounts. If you check few pages back, you could see that they banned few user from india because of multiple account case, this shows that they dont allow it and I've never see any post regarding that they confiscate winning user's fund
How about this user as I posted before (look at the screenshot)
hi guys this is my second bet for the week for the Wales v Belgium match !
you can bet here:
https://sportsbet.io/sports/live/event/8693576?ref=tipster4Event: Wales VS Belgium
International: Euro Cup, Knockout stage
Match Winner
Draw @ 3.48
Stake: 20mBTC
Potential win : 69.59 mBTC
Proof:

Reasons: personally I believe Belgium will take the match but not in the 90 minutes, wales has a considerably strengthened defence I wouldent be surprised if it goes to penalties again. Bale and co are fantastatic at delivering attacks and particularly deadly counter attacks. full time socre prediction would easily be 1-1 or 2-2 as both have highstakes and this is wales most important match for over 6 decades !
heres my parlay for the promo guys !!!
username : Aleppo

It is very clear that this user has two accounts on sportsbet.io but seems that he is not banned. So not all multi-account players are banned. It means that they do not apply their rule regarding multi-accounts to all players, sounds like a discrimination imo. Or maybe it is a special condition for those who participate in their signature campaign?