Back in the 70's I was in Vegas with a few friends. We were downtown, and one of my friends was doing pretty good playing BJ at the Golden Gate. He'd started out betting $5/hand and had grown his $40 buy-in into $600, and by then he was playing green chips. Small potatoes today, but it got the attention of the pit boss at the GG, and in came the mechanic. I didn't know the casinos had them until I actually witnessed one on the job. She was palming cards. She was pretty good at concealing her actions from the players at the table, but I could detect it as an observer standing a few feet away. I whispered to my friend that the dealer was palming cards and he needed to quit while he was ahead. He didn't believe me at first, but after losing four or five hands in a row after a long winning streak, he decided it was time to move on. Back then it was okay to win, just don't try to win too much.