That's ridiculous, this school seems fishy more and more... most have received no communication from them what so ever... and to ask for a deposit to be put on a waitlist without a guarantee of getting in... that's crazy.
I really don't think it's that ridiculous. Because 1. CDU isn't the only program that does this. 2. CDU is a newer program (Accreditation-Provisional), thus their yield ratio of students, both accepted and waitlisted, isn't going to be as high as programs that are already established. I'm sure CDU, like every other PA school, hates waitlists just as much as the applicants do. They all want to get their class squared away and seated and move on, but for a lot students offered acceptance or placed on the waitlist, this really isn't their top choice and putting down a deposit is the best way to weed out those that aren't serious about attending their program because they were accepted or waitlisted at a different program that they want to attend more.
Side note, most programs, don't rank students on the waitlist because they don't the view the list in that way. A lot of programs want a class that have a diverse background as a whole (especially CDU). Maybe an international student declined their acceptance, so a program may want to fill that spot with a student with a similar background, even if their GPA or interview isn't as stellar as other applicants on the waitlist.