Fines are as much a part of modern football as the forward pass or taking a knee to end a game. They're handed out nearly every week, usually to a defensive player guilty of an illegal hit on a quarterback or a defenseless receiver. Despite the incredible number of fines, defenders continue to commit fouls, and the fine sums continue to add up, but why?
The curious issue here is that this is a psychological issue, not a football issue, and Roger Goodell should start taking notes at this point. His system of fining doesn't work for a number of reasons:
1) For a punishment to be effective, and we're talking about operant conditioning for you sciency types, the punishment must be consistent. You can't fine one player for a hit and decline fining that same player for the same type of hit the following week. This may be the biggest hurdle for the fining system as it seems largely arbitrary and the guidelines for punishable offenses seems rather unclear.
2) Punishment must come immediately. For the act of fining a player a dollar amount to be an effective way of deterring illegal hits, players must be fined immediately. That means the only practical way to handle the fine would be on the field. Just imagine Ed Hochuli getting on his mic, "Personal foul, roughing the passer, number 58 of the defense. That's a 15 yard penalty, and an automatic first down. Number 58 of the defense is fined $10,000."
3) Finally, and the true reason that fining is an impractical deterrent, is that the behavior must be controllable. We've seen players fined for unavoidable hits. These types of collisions are part of the game, and sometimes, a defender has no chance to avoid an illegal hit if a receiver ducks just before contact.
To drive the above points home, just listen to Von Miller's take on his multiple fines, via the Denver Post, "I don’t think I’ll change anything. When you’re playing fast, stuff like that happens. None of my (fined) hits were intentional."
In short, fines for illegal hits don't work. Get rid of them.