[DrMitchJ]

Boxes get damaged from time to time. Stuff happens. The expiration date is to make sure that they are released from the liability at some point of having to fulfill that redemption. Let's say a store buys it and the warehouse it is in has a fire. There is no way for Topps to know that the redemption has been destroyed and they would have a legal obligation to keep that card around forever, even though no one will ever claim it. Having an expiration date is 100% necessary. The date is negotiable, but I think Topps just figures that a vast majority of that product would sell by the expiration date, so the chances of someone pulling it AFTER the expiration are fairly small.
In any case, there absolutely MUST be an expiration date.

I disagree.
An expiration date is 100% unnecessary ....Think about it! Topps doesn't feel obligated to fulfill there CURRENT redemptions , so what would stop them from giving a replacement to an older redemption? Nothing! No liability, just responsibility to the consumer that buys their product and loyalty to the retailers that ultimately get stuck with product that they can't sell as easily past a certain point in time. I just bought a bunch of 2006 and 2008 boxes ... Luckily no expired redemptions. But like I mentioned earlier, a 2010 redemption should still be redeemable ... And if the card no longer exists, or was never made, or whatever.... Replace it with something of equal value.
Maybe I'm wrong, but how many people have recently ripped into boxes and pulled expired redemptions? How any people pulled a redemption, placed it aside and forgot about it and found it after it expired? I'm sure that it happens more frequently than anyone imagines.