Well, there's no doubt that faculty exchange notes on their applicants with their colleagues at other universities. The music academia world is so small, that everybody knows everybody, that the topic of applicants and recruiting will naturally come up during everyday conversation.
Schools have limited funds available, so they have to be strategic when offering their places. I don't think I'm cynical enough to believe that schools will deliberately reject qualified candidates in order to make them more accurate in their yield predictions, but who knows?
Now, judging from past survey responses here at Gradcafe - obviously it's true that the institutions have their own internal waitlist process, which means they accept the ones they really want early, and if they hear back a No, they move on to the next person, before ultimately sending out a mass official rejection towards their officially promised dates of mid/late March.
That's why, I agree, that waiting blows!
Good luck all! At this point, it's all out of our hands, so sit back and here's to hoping it turns out well for everyone!