At first glance, I was thinking the casino should be held entirely responsible for not checking their cards. However, the act of having the dealers turn high cards 180 degrees is cheating. If I am reading this correctly, the pattern on the back of the cards was closer to one edge than the other. So, the only way there is an advantage is if the dealer cooperates and turns only certain cards 180 degrees. So, if my understanding of the situation is correct, he should absolutely have to pay. At first I was thinking he just noticed certain cards had marks on them. So, I was thinking that the only mistake he made was having the dealers turn the cards 180. But then I realized that this guy is way too smart for that. The only way the edge marking would work would be collusion with the dealers.