They’re some that have been able to successfully pull off the scam - they don’t usually make any deposits, all they do is look for casinos that allow No Deposit Bonuses (NDBs) and try to create as much account as they want and then play with them and get a little balance after which they’ll send all the money they got from other accounts to one major account where they’ll withdraw from and if after withdrawing the accounts gets blocked they’ll just go on and create more accounts and continue trying to cheat the system. Personally, it seems like a waste of time and most casinos have a higher wagering requirement so they’ll have to first pass through that phase for several accounts which will take several days and then tip their main account (which will also take time depending on the number of accounts they’re using) and then withdraw from the main account (which most times is not a huge amount). It’s just a waste of time in my own opinion.