Linear Camera Profiles in Adobe Lightroom

I have added an article about linear camera profiles in Adobe Lightroom.  Lightroom applies a hidden tone curve to the raw data in addition to the gamma encoding and any user modifications.  Some users, me included, would prefer that no such tone curve be applied.  This was supposedly achievable by using the new linear camera profiles.  Unfortunately, I found that some nonlinear tone curve is still applied to all photos.