I had read something about this a couple of days ago, but though it was an April Fools joke. Apparently, it's not...
Wal-mart is to introduce a new DVD player from RCA that automatically censors "offensive" content. The technology is called Clearplay, and is already available on computer based DVD players, and has caused controversy in the past including attracting lawsuits from film directors about the unapproved edits.
My view on the issue is that if a film has parts that need to be censored, then it's probably not appropriate for children anyway. More often, it's the ideas and story in the movie that is offensive, not the couple of rude words or a few seconds of gore.
More information here