From "The Junction Boys", I had never heard of this rule before.

Reading Junction Boys about Coach Bryant's years at TAM and came across this paragraph:

"The fifties were a troubling time for a control maven like Bryant. Coaches were allowed to neither shuttle plays into the games or signal from the sideline. This meant that quarterbacks were free to call their own plays. Referees kept close watch on the frustrated men who prowled the sideline. They were prohibited from even signaling for a punt on fourth down. If a coach wanted to attempt a field goal, he was allowed to heave the kicking tee onto the field. Some coaches got cute and would place a strip of tape on the bottom of the tee to signal a fake. But if they were caught talking to players on the field or flashing the smallest signal, they were flagged."

I knew about the severe substitution rules back then but I had never heard of this before. Things have come a long way.