After further analysis I'd HIGHLY suggest Nicehash disable their API, implement captchas for making new orders, remove the ability to modify hashpower, disallow people from refilling orders, and increase order cancellation fees to 5-10%.
Maybe you should also HIGHLY suggest to ban multipools (they are an essence of coin difficulty arbitrage) and coin exchange APIs (bots steal good prices!). Also, imagine there are exchanges running arbitrages themselves! This all should be banned!
Yeah, that's what arbitrage does - targets market inefficiencies and destroys them. You will have live with it.
(I am not running arbitrages of any kind myself).