EPA don't care how the emissions standards are met. The manufacturer has to come up with a way to satisfy those standards, and the epa then certifies that method. DPF in itself is not mandated, neither is SCR (def). That's just the easiest way of meeting the standards that the epa set forth.
I went through this before and I'll do it again. As a former dealer tech, I can 100% confirm that the dealer can in fact notify authorities if emissions-tampered tractors show up at the dealer. I can also confirm that the RSM advised every single one of us to turn away "deleted" equipment, as a liability issue. IF we (shop) worked on it and, say, the owner gets busted with tampered emissions, they can track that back to the dealer and then the dealer gets to prove whether or not they did anything that might help the owner's equipment defeat the devices that would affect the emissions system. My best friend worked at a company that did support for the oil and gas industry. Basically he was a run-around guy, taking repair parts and such from site to site from a shop. Tools, etc. They had a fleet of I think 84 trucks, all Fords and all 6.4's at the time. Every single one of them was 'deleted' within 100 miles of delivery to customer. There was a shop just up the road from where I live that did fairly well deleting these fleet vehicles, he loved it. Guaranteed business. My friend came back from a drill site and had to pick up some kind of pump repair parts and some tools, and on the way back to the site got stopped for having a tail light out. Local officer noticed a large (4") tail pipe and noisier than stock exhaust. Wrote him up for the tail light (defective equipment) and also for the exhaust system as defective equipment with possible tampering with federal emissions-which was a mandatory court appearance. Judge set a trial date and they brought the truck in for inspection, brought the vehicle owner in (the company), and the company played dumb. But the paper trail was there, the shop that did the work had the payment information and the repair order. So it was a slam dunk in favor of the feds. Each truck inspected by an inspector and found to be in violation, then fined pretty heavily. Per vehicle mind you. Shop that did the work and sold the parts was also fine, more heavily. Shop sourced the parts to do all this from another company out west, and the feds went after that place and fined them heavily. All because of a routine traffic stop. We are talking fines in the millions of dollars.
you guys can gamble if you want to. I'm out of that loop.
In 2012 I had the pleasure of going through an IRS raid on the business I worked at. They indeed have a dedicated police. There was 11 employees at the store at 0900, 30 min after they opened up. Right at 0900 they (irs police) shows up and held everyone up with automatic weapons. Us grease monkeys got to spend about 6 1/2 hours being grilled by these folks, they were fishing for an answer and for the first 2 hours we didn't even know who they were, they did not identify themselves, nothing on their clothing to identify them, nothing. I try to ask who they are, they say shut up and answer questions. My coworker said that they can't do what they are doing and he wanted to call an attorney, but the agent said you can't call anyone because the phones are disabled (and they were indeed disabled, no dial tone nothing on the landlines, and our cellphones were confiscated immediately at the very beginning of the raid, along with our CCW's, pocket knives, ink pens, keys, wallets, everything). The agents had each computer in the business disconnected from the LAN, and they had some kind of devices that they plugged into the cat5 cables and the phone lines that went to each PC at each workstation. Yes, the IRS does have a police, and I go to deal with them. Worse yet, the boss got to deal with them for the next 6 1/2 years, where they were found guilty on ONE charge, of which they were 100% set up for from the very beginning, which was in 2010. 2 years before the raid. Sneaky? You bet. I'm simply saying, they exist, they do things that you would not think they could do legally. But they are above the law so what do you expect?
My experience with the feds was such that I have permanently lost trust in all federl agencies, epa, atf, irs all of them. I wish it wasn't that way but the way they handled the whold irs raid, I don't really have a choice. I wish I could also make the occasional nighmares go away.