As a new paddler member of CWWA [I have two seasons under my belt] I can say that in my experience CWWA cruise leaders do an excellent job screening paddlers out who aren't at the appropriate skill level.
I have twice been told "Based on your description of your abilities and the runs you have paddled so far, you are probably not ready for this run for the following reasons ..... You might try this one _______ and maybe this other one_____ and then next year have a look at the run we are taking."
While it was a little bit embarassing to be told I wasn't up to the level of the trip, I'm alive and paddling and appreciate that it probably wasn't easy for the trip leader to make the decision either. All in all, the CWWA cruises that I have been on have been great and were run by people with some good sense.
I may not be the sharpest knife in the drawer, but I'm not a spoon.