Would it really surprise anyone if it was revealed that stuff like this already happened with Bitcoin? Seriously, give a bunch of hackers with access to racks full of Other People's Machines, plus an obvious way to turn cycles into money, and the only surprise would be if they didn't take advantage of the opportunity. I for one expect this to be the norm for every cryptocurrency from now until the end of time. The only question is how much of it the rest of the world is willing to tolerate.