What if we just accepted "cheating" to be part of the game? Such that every team is allowed to devise their own way to communicate in subtle manners (barring the use of electronic devices). And so part of the game would be to figure out the opposing team's code. There is really no way to prevent communication when you have physical presence. If you really want to prevent communications, sit them in separate rooms and make them play through computer terminals.
Catcher signals are used in baseball, we don't call that cheating.
And to bring up another analogy. Remember how in the anime Naruto, the kids have to take a paper exam to advance? The questions in that paper were hopelessly difficult for the candidates, and it turned out that the real exam was for them to attempt cheating without being obvious.
And please don't get me wrong. I'm not saying that what Fisher and Schwartz did was ok. They were clearly violating the existing rules. What I'm saying that trying to enforce a rule forbidding communications when you have physical presence is an exercise in futility. It's just that maybe we should consider changing the rules or how the game is played.