Meh. It wasn't an effort to employ the refs to deceive, it was the Lions using past reporting to try to fool the Cowboys in a present reporting situation and muffed it up by being too demonstrative in their acting. How can the refs go and tell the Cowboys and announce a player that's not actually reporting? What they did was perfectly legal but wasn't carried out properly.
Right. There was no rule broken by what the players did. If we want to talk about it being shady, that's fine. But they expected the official to announce 68 as the player reporting, so they weren't asking the ref to keep that secret or participate in the deception. They were just counting on Dallas to not be paying attention.
Now, it's on the Lions that 68 and 70 tried to hide the intent by 68 not giving much of a hand signal and 70 giving an enthusiastic one even though he never reported. They were definitely trying to deceive the Cowboys, but not trying to break the rules (which is both saying that you report and giving the hand signal).
The clarification from the league didn't say Detroit violated a rule, just that it is up to the team to make clear to the official who is reporting. Campbell seemed to think he did that pregame, but you can't count on the officials in the heat of the moment to remember that or to accept one player weakly making the hand signal for reporting while another does a strong one, especially when he's the one who has been reporting throughout the game.
I think the only place where Detroit needs to be held accountable is blaming it on the official instead of just saying, "We needed to do a better job of reporting our intent." If 68 had given a more powerful hand signal and 70 had just done a weak one, Allen probably would have announced that 68 was eligible, and there would have been no issue.
Of course, maybe Campbell's initial conversation with the official could be considered an effort to employ the refs to deceive, but it depends on what all he said to them.