There's a good reddit post about this possibility: http://www.reddit.com/r/BitcoinMarkets/comments/1rb1mc/potential_for_evil_exchanges_to_frontrunundercut/ http

There's a good reddit post about this possibility: http://www.reddit.com/r/BitcoinMarkets/comments/1rb1mc/potential_for_evil_exchanges_to_frontrunundercut/ http://www.reddit.com/r/BitcoinMarkets/comments/1rb1mc/poten... I think it's very possible for exchanges to do this sort of thing, especially when their technology is so poor that it's difficult to audit how they match orders.