Agreed. The only way I can see for either party to cheat would be for the casino precompute a large number of shuffled decks along with the output after all 2^3

Agreed. The only way I can see for either party to cheat would be for the casino precompute a large number of shuffled decks along with the output after all 2^32 possible MT seeds and use shuffles that give the house an additional statistical edge, but I can't see this getting a large enough edge to be worth the trouble.