[RoboTeddy]

Are the price differences between markets already arbitraged to the point of maximum profitability?

(which wouldn't be 100% due to eg exchange failure risk, transaction fees, risk of getting hacked while currency is in play, etc)

[kbody]

There is at least one exchange that has enough discount, but their reputation is horrible, so if you want to arbitrage that then it's on your head. In general that's the case if there is any opportunity. While they don't make mainstream headlines, mini MTGox'es still happen, like a Polish exchange some months ago.

There are a lot of people going after it, and probably some that do it wrongly thinking they are profitable while they are not. If you look at some of those bitcoin bots, they full of wrong calculations.

[mhluongo]

Highly doubtful, considering the spreads between even highly regulated exchanges