I see why the answers were not so forthcoming, you could have done a better job with the title of the thread. Anyway, I think I would tell my number one choice what the deal is especially if its is ranked lower than a school where I have already been accepted. Did you get some money with it too? flaunt it, throw it in their face, let them know even with all the money and higher ranking, you'd rather be with them. I'm not sure how effective it will be though especially if the Tier 3 did not offer you any money.