It seems to be a common thing with Best Buy - why you should (on nearly any purchase) have them open it and verify that it is intact (they can then re-seal it with there "Best Buy" tape)
I learned that the hard way, about 8 months ago, bought a 1TB USB drive, got it home, someone swapped the drive with a 2gb one - boy was I pissed!
Managed to return it however, saying it was not working, as, it wasn't!
Needless to say, check before you buy!
Although, it was nearly impossible to check the drive I got, it was inside of a USB enclosure, but still, its quite obvious with a laptop.