Today's WSJ article about this also mentions the butcher's union, which is why there are no butchers at Wal-Mart anymore. I found [link|http://www.walmartsurvivor.com/111802.html|this] about it.
The only union success at a Wal-Mart came in 2000 in the butcher's department in a Jacksonville, Texas, store. After seven of 10 butchers voted to join the United Food and Commercial Workers, Wal-Mart announced it was closing its meat-cutting departments in favor of prepackaged meat.