My understanding is some use the term "compass" when referring to a protractor and pencil, I have never heard anyone use that term til now, quite possibly pre-magnetic compass folks referred to a protractor as a compass, but ??
Sounds like the issue is whether or not it can be used as a DMD (distance measuring device) or not and how he goes about it, etc. He is using it on an actual yardage book itself, not on the actual course, so it would seem he would be ok, but if he constructs a green size "compass" then he's prolly in trouble. I'm sure he'll be warned not to do that😉
And a point of clarification, I believe it's the PGA looking into it, not the usga. My bad on that!