Rumor is TCU knew about it and changed things up. Not sure if true but it would explain some of what happened...
In defending their school's unethical behavior a lot of Michigan fans have made the argument that it didn't matter vis-a-vis Ohio State because Ohio State "knew about it and changed things up."
I've repeatedly pointed out that this is nonsensical for a multitude of reasons:
First, even if your cheating didn't actually gain you an advantage, you STILL cheated. You aren't exonerated simply because you are incompetent.
Second, the idea that Ohio State "changed things up" on a week's prep is ludicrous. Remember that Ohio State at the time was typically running a no-huddle where EVERY player on the field looks to the sideline for the sign. That means that EVERY player on the field has to know the new scheme. This is an important distinction. If you are running a huddle then ONLY one guy on the field needs to know the signs. He can tell everyone else. Thus, you could teach the new signs to your smartest player and ignore the rest. If you are running a no-huddle then literally the dumbest guy on the field has to know the signs. We all know that a lot of the guys playing on all of our teams aren't exactly rocket scientists
Third, even if we assume that Ohio State's starters were all Rhodes Scholar level intellects who could manage to memorize a completely new sign scheme in a week, that would still be an advantage to the cheaters because all the time Ohio State spent learning the new sign scheme is time that they are unable to spend watching film of and prepping for the cheaters.
Fourth, even if we assumed that Ohio State's starters were all that smart and someone at Ohio State invented a time machine so that the guys could learn new signs without cutting into their other practice time there is a decoding advantage. As a history buff I've read a LOT about the US and British decryption efforts during WWII. One thing you will learn if you read about that is that the Germans and Japanese did periodically change their codes and when that happened it took the US and British a while to crack the new codes. However, cracking the replacement codes was VASTLY quicker than cracking the initial code because they already knew the structure.
The same thing applies here. Even if Ohio State did change their signs, the cheaters already knew the structure of Ohio State's sign system so it would then be easier for them to crack the new code in game.
In TCU's case, some things are different:
First, from what we have heard, the cheaters illegally scouted "likely" CFP opponents. That is why they bought tickets to the SECCG and to some Clemson games, etc. However, they didn't consider TCU to be "likely" enough to warrant illegally scouting them so the cheaters ignored TCU and didn't have illegal advanced scouting on them.
Second, it was announced that TCU would face the cheaters in the CFP Semi-Final approximately five weeks before the game occurred. Thus, if TCU needed to change their signs, they had five weeks to accomplish that instead of the five days that in-season opponents had. That makes everything above a bit more achievable.