Maybe that is the best way to identify the spy. However, I think that a pass play with crossing routes could also serve the same purpose. And if no one is open, Taysom can run it and again the spy would be known. I am not against Taysom running it, I am against called QB runs where he has no other option but running it, and it isn't an important (3rd or 4th) down or when it isn't in the red zone.
But you bring up a good point.