Seriously though, L or R dosen't matter as long as they are all the same on the shaft.
As for the reasons why we do what we do...I don't know, there are some good posts before me on that subject.
As for safety I can say this...I got stuck real good by a quill just once...I wasn't even shooting, just pulling the shaft from a butt.
I now sand the quill to paper thin and trim the point off of all my feathers. A dab of glue on the very tip of the point helps keep it from lifting. I used to wrap some thread (which really makes the bond strong) with glue but no longer find it necessary since I sand and trim the quill.