In the first CAS match I ever shot, I used a crossdraw. In order to "do it right" I used as straight draw holster slid around to the off side. Drew straight up, finger off the trigger, thumb off the hammer. Did not cock the gun until I had it pointed down range. Shot the match one handed, and beat Edzilla by something like .010 second.
Of course, that's the only time I've ever beat Edzilla!
I don't think that an authentic crossdraw holster is dangerous, as most of them that I've seen don't have much rake, if any at all.