Given the narrow beam of the lidar, mounting location of the RD, and what not, it is relatively straightfoward for lidar detection from the front since the windshield is generally free of obstruction.
Most RDs market their rear detection (I believe 360d is the term used). The V1 and the X50 have a rear facing sensor that is relatively unobstructed. I can't really say that for the Bels (most models if not all) - mounting under the RVM causes even more obstruction. Anyway, to get back to the point, most vehicles have a lot of obstructions when looking back - head rests, tinted windows, stickers, bunnies/bears, passengers, etc.
Doesn't this make the rear reception non-existent (or remote at best)? Even the fabled V1.
EDIT: Yes, it IS uncommon at this time to be hit from the back, but it's being done. If one is hit from the back, I guess one would want to know so that one can 'mentally prep' for an answer when the LEO walks over for license and registration. Or opt in for other countermeasures.
So how do feel about its value to you?