For those unfamiliar with bitmarket.eu: It's an escrowed bitcoin exchange: When two parties agree on a trade the bitcoins are held in escrow by bitmarket.eu, until the former owner releases them (typically once the agreed-upon amount of flegacy currency has been transferred).
I've been trading bitcoins there. However quite often, the other party failed to "pay" (transfer legacy currency) - in all the cases of non-payment this was after the BTC/EUR rate dropped.
Thus escrowed trading offers risk-free profit to fraudsters: Buy some bitcoins on bitmarket.eu, wait for a few days, pay if the BTC/EUR rate has gone up, don't pay if it has gone down.
This seems like a significant probem to me. E.g. out of the 9 transactions I did on the 10th of last month (BTC prices did fall the next day) I only received payment for 5. For the other 4 transactions I never received the EUR.
Philipp
Welcome to one reas on I prefer exchanges to OTC.