Back in the 70's when I first started going to Vegas, the changes in luck in Blackjack with a dealer change weren't always random. I witnessed a casino altering their regular dealer rotation to put a mechanic in to deal the game. She was palming cards. She was good enough at palming cards and faking a shoe draw to fool the players sitting in front of her, but standing back and a little to the side, I could see what was really happening. She was brought in to take down a friend who was up. I whispered to him that it was time to leave. He played about 6 more hands, losing all of them, and walked away. He was more than a little pissed off when I told him why I told him to quit playing, but any protest back then wouldn't have been healthy...