Beating Vegas was a really interesting doco. The casinos spend so much money and resources on their business to ensure their continuing profits. The show reported how each table at the casino is expected to make a certain profit, and if it falls short, then they start to investigate.
The casinos now get the MIT students' yearbooks and scan them into their databases and use facial recognition software to identify these card counter players, and then when they're spotted, they're asked to leave even before they reach the table.
It mentioned an area of the face (I think it was the cheekbone area generally) that can't really be changed so they use that to identify people so they don't even have to worry about wigs, clothes, or any other disguises the people come up with.
The documentary reported that casinos have the highest levels of security and surveillance anywhere, and that when the 9/11 event happened, the casinos were consulted for advice on how airports etc could improve their security systems.
At the end of the day, gambling is designed to benefit the house, not the patrons. Everything is designed and geared towards profits to the casinos. You never see any windows to the outside world and you never see any clocks...