From what I have seen over the years, usually after you get the fed's attention the first thing you receive is a cease and desist letter. Smart people cease and desist and never do such a thing again.
You never know who is going to handle a case. One fed considers $5000 a major sum, another doesn't consider $500,000 a major sum.
One year the IRS decided I owed them $145.00. If you say so, I sent them the money. The next year they said they owed me $145. I told my tax man, no problem, they can keep it!
Some friends were making a little 'shine. The feds watched them make a million dollars worth, wholesale, then raided. Took five pick-up trucks, the big trucks belonged to U-Haul. Did a little more damage and fined them $5000 each, $25,000. Five years probation. I know of other people that did far less and did basically natural life as first offenders. Messing with the feds is like poking a bear with a stick, never know when you are gonna poke a tender spot.
Hu