Several forum members have given first hand accounts, from various locations. I'm sure backroom deals are going on, but I'm sure it's not a ubiquitous problem either.
First hand accounts? So you are saying there are forum members involved in such goings-on?
Sorry, but you are going to have to cite some threads to justify this. All I have seen so far is a bunch of people claiming it goes on, believing it must be happening.
There are threads like this one where folks claim it is going on, but these are not first hand accounts of it happening. Plus as noted, if the employees are buying the ammo, which they may be allowed to do as with other goods from Walmart, then there is no foul. It isn't a scam.