Would such a formation even be legal..? That same phrase is in the definition of a lineman... (2-30-9) If the snapper isn't facing the opponent's goal line, then he isn't a lineman... At the same time, he isn't a back... Therefore, you have an illegal formation on A... (7-2-3)
I think this is a "clarification", but perhaps it's not all that clear what they were clarifying...