I think Gern's post is spot on. Really, go on the interviews that you get, to places you would like to go, and rank them according to whatever system you devised, and then wait for match day. The Match is designed for YOU the applicant to match in as high a spot as you can. There's no point in gaming the system, and really, whatever email the PD sends shouldn't really factor in the equation. If you interview at program X and think it's a long shot, but would like to go, rank it number one, regardless of whether the PD sends you an email, generic or not.
I think things that can help sway PD's and adcoms is to do an away, to show them that you are interested, like the city, etc.. That having been said, doing an away in anesthesia is nowhere near as necessary as in some other fields.
The long and short, soon to be MS4's, is that you should do exactly what the instructions for the Match tell you to. Go on interviews, and then rank programs according to PREFERENCE. You have nothing to lose by ranking them this way.