Well on theory the chances on deal or no deal should be 1 in however many boxes there are (I don't remember how many) BUT.... does the banker know what's in the boxes? It is never actually stated to my knowledge that the banker doesn't know. I know the boxes are sealed but is that just for the benefit of the contestants and the host. Yes there is also the spiel that boxes are chosen at random by the contestants but, if the banker is aware what's in them, and his bank balance is a little low he may only give the option to switch if the lower value is in the contestants chosen box. Another way to ensure that the game is a little more controlled than we first assume?