" ... manufacturer who doesn't care at 
all about board outline on all layers (read: CAM ignores them "

My point exactly. The CAM process entails modification of many of the artwork features. If CAM is failing at something as simple as suppressing unwanted board outline you can be certain the entire CAM process is suspect. It should be noted that a fundamental check performed by every fabricator is copper to edge clearance; fabricators don't like to spend money on replacing route bits more frequently than required as it adds to overall process cost and routing copper edges wears the bits quicker than bare substrate material.

My approach is to include all of the information and leave it to the CAM folks at the different vendors to tool per their requirements. I prefer this to having situations where features must be interpreted from other artworks and added to data I've produced and reviewed for accuracy.

If I had any intention of sending a design for "No-CAM" cheap prototype processing (? do these still exist) I would change my approach.