They were definitely not successful. Anyone looking at BTC prices between NA and Korea saw the arbitrage opportunity. The fact that it sat there so obviously

They were definitely not successful. Anyone looking at BTC prices between NA and Korea saw the arbitrage opportunity. The fact that it sat there so obviously for so long was a testament to how impossible it was to profit from it. In fact, the whole reason for the pivot to an exchange from a pure arbitrage play was due to their lack of success.