Even if it is a mistake, Amazon's policy is that they sell you a pre-ordered item for the lowest price that it was between the time you pre-ordered it and the time it releases.
So, say you pre-order MGS4 at $59.99, and it randomly drops to $29.99 a week later by accident, then goes back up to $59.99, you'll get the game for $29.99 when it releases. :D







