I'll try to make it clearer. The OP and the point of this and other threads is the hash power not the potential for someone to gain or lose trading at cex.io. It is completely irrelevant if everyone sold their cex.io hashing power today at a loss or gain. Ghash.io would still have the hash power and possibly even more incentive to do something untoward with the blockchain. People are pointing their own miners to ghash.io. That's what OP wanted to figure out how to stop, or at least slow.