> How else do you get what might be illegal products off the shelves?
Your premise is that there is a difference in the product.
The product is a piece of hardware that connects your phone/laptop to the car's computer. Are you using it to program the computer to bleed the brakes, or are you using it to program the computer to defeat emissions tests? It's the same hardware dongle either way. A roll of duct tape isn't a different product when it's being used in the commission of a crime.
You can try to prosecute companies that actually ship the thing with software to defeat emissions, but that doesn't really do any good. People would just get the generic hardware from the store and the defeat software from anonymous third parties over the internet.
If you actually want to stop it, try one of these: The old style emissions tests, where they put the car on a dyno with an exhaust probe, have been mostly phased out because the equipment is a lot more expensive. Keep some of it around. Then when someone goes in for their emissions test, roll a D20 and if they get a 1 their vehicle is taking a trip to the full service facility and if the exhaust probe says something different than the car's computer their car gets a free forensic analysis to check for a defeat device. Finding one means jail time.
Your understanding about how this works is incorrect, I think that's the problem.
If a product being sold is primarily being used for a purpose which violates the law and does not otherwise have fair usage the government can and has pursued and won legal cases resulting in the product being banned. That is no different here. The reason for interviewing consumers is to help determine what the product is being used for to help inform the legal case. It may turn out that it's primarily used for fair usage or "practical" purposes which don't violate the law and the DOJ may drop their case. It may turn out everyone is using these to violate the Clean Air Act in which case it will likely and should be banned.
> A roll of duct tape isn't a different product when it's being used in the commission of a crime.
If the vast majority of the time the roll of duct tape was used in the commission of a crime, it absolutely could and likely would be banned.
> If the vast majority of the time the roll of duct tape was used in the commission of a crime, it absolutely could and likely would be banned.
Which continues to be an absurd premise. So if the original use case for duct tape was kidnappings then it should be forever banned because a sample taken at that time had that statistical distribution, and thereafter no other uses can be adopted because it's banned?
It seems a lot more reasonable to prosecute kidnappers rather than the makers of generic tools.