Very common practice
Looks like WalMart has taken a page out of NewEgg's "Revenue Maximazation" training manual for employees. This has happened to me so much at NewEgg, I no longer shop there. Out of 14 orders placed during 2006, 4 of the products were obviously repackaged returns. This situation was confirmed when calling the manufacturer of a video card who informed me that the cards' serial number had already been registered.
The surprising part was the video card manufacturer telling me to contact NewEgg for an exchange and that they really had no procedure in place for dealing with shady dealers. They agreed it was a valid concern, but could care less about taking info and contacting NewEgg directly. I don't buy video cards from this manufacturer anymore.
The retail marketplace will shout "Caveat Emptor". Buyers of repackaged product need to inform the retailers "Caveat Venditor". This illustrates the problem with the US economy, the corporations have waaaay to much arrogance and power to do as they feel, and to heck with the law. Things seem to be a little more civilized in the UK about such matters. The Trading Standards are actually in place to protect the consumer from dodgy retailers. Fancy that!