My program did sent me an email right after my interview, stating that they ranked me highly on their list, and this is one of my favorite prg too.. and before their deadline of rank list of the applicant, which was 2/15, they sent me another email, saying the same thing.. i did rank them as my no. 1 choice at the end, and i matched there.. So, the bottom line is, rank according to your preference, dont let anyone influence you. (in my case, they did influece my decision a bit ... lol), just remember MATCH process is favoring the applicant side.
ps: one of my friend, matched into Radiology, she got a FEDex letter, the next day from the prg, saying the same thing, and she matched to that prg too.. so, use your judgement.