The reason I'm almost sure of the fact that Wal-Mart movies aren't altered from their theatrical release (other than the large number of movies I've bought there) is because of the fierce manner the MPAA protects their films. A few years ago, a company tried to sell "family friendly" movies with the profanity and the nudity edited out, and the MPAA went nuts.
I remember that; I think it was a single store or small chain, and they were copying the movies onto blank tapes IIRC, editing out the "bad stuff". That's messing with copyright.
Mall*Wart, IIRC, insists on a MW version of the tape/DVD from the studio, or they don't carry it. Like the CDs.
Like I said, I may be hallucinating this, but hope someone will help me out here.