V-Bloc can twist and will put torsion on your action. Also nothing guarantee they are perfectly straight. Not saying they are crap. They are very good but bedding it will maximize the benefits of this great chassis. Also Ever had a rear screw coming loose sometimes?

That is why. Loctite? It will only hold it in place but the problem under will still remain. Harmonics will now be consistent. And there will be no POI shift. Of course we are talking pure precision here. If you are not in that well the normal chassis will do is job just fine. See in the #2 picture... The side V-bloc "rails" a suppose to fit the action and center it. Well at many places there was no contact. This created torsion on the action.
http://s5.photobucket.com/user/CaptFLAN/slideshow/AIAX build/Bedding AI
cheers.