The only two weapons we have to play with is the carrot and stick. And it turns out that it's very difficult to get stick to work, but that's essentially it. We actually want these puzzles to be as useless as possible because if you could use your machinery for something else, then all of a sudden the cost of attacking goes down. But what we really are relying on is the block towards being high enough so that you would just choose essentially to make a shit ton of money instead of cheating.