You do realize that NitrogenSports' spread/vig is well under 10%, meaning that the EV of any bet that someone makes is less then 10% of the bet. It would make no sense for NitrogenSports to pay out 10% of losses when they expect to make less then 10% of your bet.
This is something that could easily be abused as you could make two opposing bets on two different accounts, and claim the rakeback award on the account with the loosing bet and end up with a profit. NitrogenSports is not that stupid
Sports bookies don't give away free money? Shoot. Maybe somebody buys this and gets a legit money printing machine.
NitrogenSports has a referral program, I believe it is something along the lines of 1% of the smaller of the bet amount or the potential to win amount, so I would somewhat believe if they were to offer maybe 2% of losses on sports bets, but I think even this is pushing things.