While it does appear that the advance warning of Fastlane being down is a reliable indicator for when the results are released, March 18th seems a bit early. Going back a few years, only 2007 was released in March. (I pulled these dates off previous gradcafe forums, let me know if they're wrong) 
 
2007- Friday, March 23 
2008- Tuesday, April 1 (Results were apparently accidently released\hacked the day before) 
2009- Friday, April 10th 
2010- Tuesday, April 6th 
2011- Tuesday, April 5th 
 
So March 18th would be the earliest its been released in awhile, but that will not stop me compulsively checking Fastlane early Monday morning. 
 
Perhaps this has happened before, do we know if the "Fastlane will be down" advance notice on the website around late March\early April always means the announcement will come?