To paraphrase NCAA axioms and NCAA clinicians. When WR are out wide, why split hairs to whether someone is on/off/ et al? When in dobut, it's legal. Who are they fooling out there?
On the other hand with linemen and wing back, allow once if they are in 'no man's land' (in the backfield) as there can certainly be an advantage gained (i.e. pass play) - although I can never remember a wing back lining up incorrectly. After the one play, communicate to A's coach and maybe R can pass along the word to A in the huddle. After that, flag it. Once a few flags fly, they will get the hint and adjust.