Exactly as RascalMafia said it is easily tracked in every way. There is a paper trail with everything involving programming an ecm. That paper trail has a source. There is no such thing as an anonymous flash. We have found most dealers are out for blood as well. As soon as they see something that isn't kosher they relay it up the chain. We had a dealer who was deleting EGR on ISX engines get nailed. They thought their laptop was "top secret". Turns out they were using discs from another dealer they obtained. The dealer who the discs originally belonged to got contacted. That dealer was not going to take the heat so they ultimately threw the dealer doing the deletes under the bus.
With the EPA, emissions, warranties, etc... somebody always ends up paying. They do not just give up because it is the easy way out.