I am wondering about the practical consequences of having one color channel blown out (say in a photo with the frame mostly filled with a red subject, with the red channel blown in the brightest areas) - is this always to be avoided (by reducing exposure?), or is it sometimes OK (as there are still 256*256=~65K color values available for those pixels), or ?? - can any generalizations be made?
If the red raw channel is blown, data will be lost. However, if the red channel is blown in the rendered image, it may still be intact in the raw channel because of the white balance multiplier. For example, with the Nikon D7000 and exposure with daylight (CIE-D50), the red channel is multiplied by a factor of 2.11 as shown in the DXO
data base for this camera (click on the color response tab). In this case, recovery can be successful with no data loss.