I'm not trying to be a killjoy here, by the way. I just hate the idea of hundreds of the smartest people in the country wasting a week of their lives calling NSF and hitting shift-reload in their web browsers. If only 52 of us do that then we've wasted an entire year of NSF-applicant quality brain power! Look how many reloads this thread has gotten already.
I'm sure there's no way they'd update the site to include "or early April" if there were really any chance that the results would be out in March -- bureaucracies just don't work that way.
If results come out tomorrow or Friday I will print out my NSF rejection e-mail, film myself eating it, post it to youtube, and link it from here.