Nothingness:
It may be a rare thing to get into that situation, but I have at IYT. There, my opponent didn't agree to a draw, so I had to request support to enforce the rule. The game was declared a draw even though my opponent didn't agree. With nothing in the rules here, a game could go on indefinitely with no progress. The more patient player could effectively force the less patient player to resign a game that should be a draw.
Unfortunately, there seems to be little interest in adding a draw situation to Espionage rules here.