The Borgata alleges that Mr Ivey and an accomplice gave directions to the dealer to flip the cars in a specific manner, citing superstition. The casino accommodated Mr Ivey’s request, it says.
This is presumably what the casino is basing its argument on.
But, the dealer/house controls the dealing of the cards, they did not have to accommodate his request. Ivey had no control in this regard, save for a simple request. The only reason they would accommodate such a request is because Ivey is a huge spender (and therefore huge occasional loser) at their casino.
It is the same as card counting IMO. Not illegal but against house rules. What does make card counting illegal is the use of some other device to help with the counting. It’s a very very loose argument, but I wonder whether the casino is going down the route of suggesting that his “manipulation” of the dealing of the cards was to assist his counting of the cards. I still think the casino could have taken proper precautions, i.e. not having a player dictate how the cards should be dealt!
(fwiw, I think Ivey is a legend. Always liked him as a player)