Sly cheaters can actually devise brilliant plans to allow themselves to prosper. In such cases, they deserve it too. It's just like how a guy can pretend to be handicapped and after attracting sympathy from people and contracting a few donations, he can leave a picture of himself with the money in his hands with the captions "PWNED YOU F---ING LOSERS!". If he is able to pull a con like that and actually fool people, he more or less deserves the money :P.
I don't get the "If practise makes perfect, and nobody's perfect, why practise?" part though... In what way does it concern me?