That might be the case, but the tentative offer I got said "Participants must attend the EAPSI Pre-Departure Orientation on April 3-4, 2014 in Arlington, VA. Information on how to book airplane tickets and hotel room at no cost to Fellows will be provided if this tentative offer becomes final." so that makes it sound like they will finalize the offer before DC. It might be officially done in DC, but they wouldn't fly us out there if they didn't expect to finalize things. Besides, as I understand it, the tentative offer is like when our grad programs say they accept us, but we still haven't gotten a letter from the dean. It's as good as done barring any crazy circumstances, which is why (at least for Japan) we're supposed to look into housing options even at this stage. ...that's not to say it won't be nice to officially know!
I guess we'll post which comes first (letter sending us to DC or letter that finalizes our acceptance) when it happens.