In parallel with the Lens Instant Savings, there's also a new round of camera instant savings from Sony DSLRs (A58 w/18-55 for $550) and Olympus M43rds. Here too, the prices are "synced" across authorized + reputable Sony dealers as soon as their servers catch up with the new pricing. No expiration dates are mentioned.
"Synced" is a euphemism for price control and price stagnation. If the camera manufacturers really cared so much about local stores, they should be selling them their cameras at a steeper discount, that way the local stores have more flexibility - they can price-match the internets or even sell for less. But we all know the manufacturers don't care about the local stores. They are using them as a shield to cover up their roundabout price control.