Did they change the 2015 Ladder Season 1?
Yesterday i was set to 6 april when you look under matchmaking.
Also Blizzard stated the lock to be accordingly
http://us.battle.net/sc2/en/blog/18382014/2015-ladder-season-1-lock-incoming-3-23-2015
Today it was set to 13 april with the lock 1 week earlier.
In EU we have the easter holidays coming, so it would make sense that ppl get the holidays as a last chance to get promoted, also it could be that since LOTV beta is coming, they dont want ppl to be "bored" in a locked season while others are enjoying LOTV beta.
Treznor