Almost every day some people are here coming with an idea of going for arbitrage trading. But I'm not at all hearing any successful making use of those opportunities. Yes, I am well aware of there might be many practical hurdles, still I love to hear any success stories of easy profits by trading with price gaps.
The price difference between the different exchnages were quite low and huge variations can be experienced at times when the economic situation in particular Country collapse. So we need to have access to buy anywhere and sell anywhere which is quite hard. Recently I found this big variation in the Indian market during demonetization. In India it was selling around $300 difference compared to the rest of the world.