I feel the Seminoles have much more to lose than gain by cheating. Even with a player playing perfect BS, the house edge is still high in their BJ games. ($25+min tables have around a 0.5% edge) Think of how few ploppies actually use BS, and realize the Seminoles are already making a killing on the ploppies who play "on a gut feeling." If civilians were to find out that the games were fixed, they would (hopefully) boycott the games. The potential of such negative press makes it in the best interest of the Seminoles to keep their games fair and continue to profit on their monopoly and their poor conditions.
Most casinos make a large majority (usually 80%+) of their revenues from machines, so taken into account that slots are their most profitable and popular assets, why jeopardize their business by fixing a couple card games to make a few extra bucks?