I'm waiting on Yale too, but it's come to the point where I'm visiting a school every weekend (except Easter) until April 15th and I really can't miss any more class than I already am... I'm not going to Yale without visiting (MIT or Caltech, I'd think about it, but that's it) nor am I being rude enough to cancel on schools who have purchased airline tickets for me. So should I get in, I'll decline, and if I don't, I won't be upset because I'm not sure I want to go to a school that strings you along like this - I'm just imagining submitting forms for defending in 5+ years and not hearing back from the administrators for weeks...
Tell me yes, no, or waitlist already - if every other school with a Jan. 2 (and 15th, for that matter) deadline can by now, so can Yale.