A smarter criminal would have opted for g2.2xlarge instances as well as mining for a currently more profitable coin. Granted he'd need to be careful not to leave a trail, he could essentially trade these coins for LTC and still obtain more litecoins.
I'll boinc on my desktop for science and goodwill but will not waste any more time on Ripple's program or indeed on Ripple itself, as brilliant as the idea is. Ripple's founders are hanging on to their 60%+ outstanding Ripples so tightly that I suspect the project will never truly get off the ground.
As much as people criticize it, I think some variation of Bitcoin's seignorage mining is the only realistic way to bootstrap a successful virtual currency, at least at this point.