Somebody tried to feed me this a few years back, I didn't buy into it. However I am surprised to the number of players who seem to play this way.
Sitting at last base and the dealer has a 10 showing, the player may have a low 12 through to 16. Basically only two specific cards are going to help you hit either 20 or 21. You have more chance of NOT getting the card (for the non-counters).
Therefore rather than risk the bust, stand hope the dealer doesn't hit the 10 value card, rather gets a low card and then a 10 value card forcing the bust.
I'm sick and tired of people who don't have a clue about this game occupying the last box making these kind of moves, so I usually try and aim to take last box, however I am get peeved at the number of times I bust hitting a 14~16 against the dealers face up 10.