Today you will learn that USF units are quite bad at hiding themself from enemy!
I've spotted this when stolen raketenwerfer attacked my Panther, and I was really confused that I was able to see crew, but gun wasn't anywhere near. Then I went off to Jannes cheatcommand mod and did some SCIENCE!
As you can see on this image below, there is total of 9 Raketenwerfer crewed with pretty much every USF infantry unit, including recently added Rangers. Squads standing next to Raketens are the exact squads that the gun was crewed with (except for captain, because he killed 3 models trying to rocketjump with zooks)

And here you can see the effect of using camouflage ability - only pathfinders were able to actually hide themselfs along with the gun.

As far as I can tell, this only applies to USF infantry.
Also, after crewing Raketenwerfer43, my Paratroopers switched VOs with partisans, that was pretty hilarious.