If you look through this thread

you will find a number of posts that said that the CDP course was not required if you had either the Black Badge or PPC holster course. While it is desirable to have the CDP course it was never a requirement.
Last year I had a beef about having to be a member of CSSA (or join at the time of the course) in order to shoot in MDPL. (I thought the extra cost will discourage some who may want to try xDPA)
It was explained to me that you don't have to be a member of CSSA in order to shoot, that other holster/safety courses were acceptable, that CSSA membership was only required to take the CDP course, not shoot in a match. At that point I felt I was not being blackmailed into joining CSSA in order to shoot MDPL. I ended up joining CSSA on it's own merits prior to deciding on taking the CDP course.
I still would like it if it was not a requirement to join CSSA in order to take the CDP course. I think we could get more shooters this way. I have concerns about CSSA's involvement in this sport.