I've purchased a few batches of these and have been circulating them. I've checked every single one I've gotten against Block Explorer to verify their stored value. I've had no problems with these at all, and they make great conversation starters (:
Do you mean you have opened them all or that you have checked the firstbits? Because, if the latter then you haven't really checked much. I think it would be fairly easy to search for 2 addresses with the same firstbits. 7 digits isn't enough to rule this out.
Anyway, I want to get more.