Welcome to reality. Laws are broken all day, every day. Most are deemed not worthy of investigation, they have limited time and resources.
You would not be charged for a crime, they would tell you to stop, maybe a small fine at most I'm guessing.
But who would tell? The banks benefit, you benefit...so the two of you keep quiet. Your fraudulent activity is not dependent on the bank.
Meanwhile, the defendants in this case did it for many years, over and over, on many things. They made enormous gains. And they are NOT being charged with a crime on this so far, just civil action (penalties for breaking the law).
And they were investigated as part of other ongoing criminal investigations, which is key here, and in most similar cases. Someone has to blow the whistle, and it has to be a big enough case or egregious enough to warrant investigation.
Once investigated and they find evidence of crimes, they are under an obligation to consider legal action.