There are three dates being floated around for Games Workshop releases that have been blacked out for store employees. Three dates would be good indicators of several big projects that are expected, like the Deathwatch Board Game and quite possibly a rumored Adeptus Mechanicus full codex release.
Im going to assume that Feb 28th was a typo, and that February 27th was the intended date.
If the first date is meant for the suspected Deathwatch game, the actual date would logically be March 5th, since pre-orders are expected to go live on the 27th and the game released on March 5th. So I don't know what to think of these blackout dates.
The other two could be just about anything. From Ad Mech to AoS. A full Adeptus Mechanicus codex has been rumored. You can see those rumors from Squiggly. http://natfka.blogspot.com/2016/01/full-admech-codex-incoming-new-flyer.html
If anyone has further information on store employee blackout dates, please forward to firstname.lastname@example.org. Even it's just to confirm.
via Captain Citadel on Spikey Bits Forums
A mate of mine passed along that GW has blacked out the following dates for their store employees: Feb 28, Apr 16, and May 7th. I assume that means big releases on those dates.