Entering mid shoe without backcounting
Not sure but I think you are asking about entering a shoe game, mid shoe and are wondering if this is effective. You will already know how many decks have been played by looking at the discard tray, so two decks in the tray, 4 decks left.
This is not an effective method of play because you have very poor penetration. In my example, if two decks have been dealt and 1.5 decks are behind the cut card, you are looking at around 40% penetration.
Often, when I see a dealer who cuts only about a deck, I might sit down near the end of a shoe so I am in for the start of the next shoe. In this case I just flat bet till the next shoe, but more often I just wait and enter after the shuffle.
ihate17