I'll be honest and wonder how no one caught it sooner. I mean handsize should of been a dead give away. Someone should of noticed he had a lot more cards in his hand then the other people did.
As far as why...
I learned a lot about cheaters when I helped run some online tournaments for XvT and JK back in the mid 90's. Big things with sometimes 1000+ people playing, so we had a number of cheaters.
Part of what I did was track down people posting fishy scores and investigating it. What seems to me, was that some people believe if they can get away with it, then they deserve it. The fact that there's nothing on line doesn't factor into it.
They aren't doing it for the prizes most times, they're doing it because they think they're smart enough to get away with it, and since that's true they deserve the victory. It's often less about winning and more about proving they're smart enough to fool everyone else.
Edited by VanorDM