Maybe he will offer something that is very profitable but the risk to his gambling account is also high when one day it can be banned by any Sportbook.
I'm not really sure if Op really does bad things on every bet in the Sportbook but for sure this is definitely something suspicious ...
What op offers should not be important but to know why his accounts are being limited in casinos because if he has access to another account, same limitation will happen after awhile. I think there are two possible reasons that casinos do limit player's account and that is if you are lucky to keep winning over them (but they don't openly admit to this). Another reason is when the account is flagged for suspicious activities and bypassing the rule in ToS.