There is no hack guys, having 2 paladins is caused by the delay in the TW server, in which your command of creating a paladin is sent to the TW server. It must be around 10 ms (random number, I don't know either), and if you manage to make the second paladin before 10 ms passed, the server doesn't know yet that you have a paladin so it gives the command again.
Matt doesn't "hack", maybe he uses a script (can be considered mini-bot) to achieve that speed. The only rule he is breaking is not reporting the bug but keeping abusing it, knowing it's a bug