Accusing a player for arbitrage betting is nonsense unless we speak for completely wrong odds/lines etc. No need to mention that you can never be sure if bettor truly arbitrage or not. Those banned scanning services you mentioned provides 100's of potential bets every day. How on earth you are sure that he is arbing? You are not. He could easily searched for best odds in the market and simply chooses you. Is he responsible cause his bets appeared on those scanning services? Obviously not.
 
You can limit him if you don't like his activity but he deserves to be paid every penny.