But surely Glen if you stop at step 2 you are in effect being offered a choice of either the box you originally chose or ALL of the remaining boxes. This is why I used as an example 100 boxes. If I said select 1 box and then said you can keep the box you selected or swap to the block of 99 boxes remaining, it becomes a no-brainer. Okay, with 3 boxes the odds aren't so clearcut but the fact remains you are being offered either 1 box or 2. I'd always take the 2. The fact that one is removed (and you know it's empty) is really just obfuscation
