Right. The school in question is sort of on a mezzanine below the first tier but above the second tier. It's a good school, but everyone who gets into a first tier program later on would go there instead, right? I think this is part of their strategy to increase yield. At any rate, I went ahead and e-mailed three of the other schools which usually sent out decisions in late February/early March. Two ignored it but one (which I thought I had low chances for) actually called me today for an interview!
I think it can work but you need to be careful - it helps them to know that you were accepted somewhere else good, but at the same time they may think you won't go to their school if they can't get a decision to you in time.