I arrived very early and played for about 2 hours before they changed cards. When they did, I left and ate breakfast but about a hour later I returned to a different table that presented the strangest opportunity I have ever experienced. I was playing a 6 deck shoe and during the first shoe I played I watched the 5 of diamonds come out of the shoe stuck to the back a 4 of spades. Yes, 2 cards together. The dealer pealed them a part and played as if nothing happened. The 5 had a red smudge in about the middle that the dealer ignored. Hmm, the next shoe the player to my right drew and again the 5 is pealed off of a 9, I wave off the 5 because I'm sitting on a 20. Next shoe near the end with a tc high enough that I had out a $500 bet with a stiff 16 the first baseman draws and busts but the 5 has once more been pealed off and tucked...waiting for the next draw...no one takes it...I was going to surrender but opportunity knocks, I take the 5 and beat the dealers 20. Unfortunately, the 5 never came back into play for me the rest of the session. I am amazed that something as stupid as 2 cards sticking together was so useful...no tracking,steering, or cut card placement needed.