I get all that, I just don't see it being only Michigan. Again it goes to the fact that teams advertise their signals because they think that the benefit of going fast outweighs the cost of the other team potentially reading their signals. It also goes back to, if you do that, and you don't change them from week to week, that's as much on you as it is the other team. I mean, for crying out loud.
I am in no way a Harbaugh apologist. I'm just saying that if certain other coaches did the same thing (and I bet they probably are), the NCAA would find a way to blow it off.
IMO, if you're worried that the other team is looking at your barbecue and hamburger signs and figuring out what you're doing with them, change it up before you play them. Again, if you're signaling in plays that way, and you're not assuming that the other team is seeing what your signals mean from previous games, you're not doing your job right.