It turns out that Walmart's "rollback" of the Xbox 360 4GB Kinect bundle, dropping it to $249 ($50 off its current price), was an error. A notice posted by Walmart acknowledges "the price was mistakenly labeled as a rollback," a term the retailer uses for permanent price drops.
The silver lining here is that Walmart will honor the $249 price at retail until Monday, September 5, or while supplies last. There will be no rainchecks on the offer.
Microsoft informed us last week that it does not discuss pricing plans in advance, but that "Walmart made an independent decision to implement this temporary price cut."