Scrapyards already need licenses (permits). Adding licensing requirements will just result in the people with licenses buying from the thiefs. It's just another middleman in the chain.
If anything it makes the problem worse because scrapyards often do turn away obvious thieves. A mechanic showing up with ten legit converters and forty stolen ones he bought off the thief gives the scrapyard plausible deniability. Furthermore it moves the illicit transaction outside of a legit commercial establishment and to wherever the thief and the mechanic care to meet.
It's already acknowledged that without enforcement against the people who are actually cutting the cats off regulatory requirements just displace the problem and shift the profit around.
Being a mechanic doesn't require a license although running the commercial establishment generally has some permitting requirements.
Lets think about this situation in programming terms. "Fixing this exploit will just result in the people finding another bug to exploit".
Well... yeah. That's the point. You don't necessarily want to stop all crimes (I mean, you do, but that's just unreasonable). Everyone is happy with simple deterrence: making crime harder to do and harder to logically manage.
And you keep fixing the law until the criminals / unwanted behavior is finally fixed. You gotta start somewhere, much like you gotta start fixing code exploits if you want to fix the security in your software.
1) the mess that is DRM, whether for software or media, and
2) to the point of 10-step windows activation (including phone calls and having to reinstall because one version only takes retail keys and another only takes oem keys and another only uses network auth), and
3) video games that try and re-authenticate between every frame of play
And tons of other "fixes" that just punish users and don't really deter bad behavior.
Software is bad enough; we shouldn't need to authenticate our exhaust system before recycling it.
The answer is mitigated risk via insurance and prevention, not a preemptive policing of all privately owned items of value.
I am quite skeptical that this is true.
The "Mechanics License" is an informal certification that all reputable technicians in the US employ and is widely recognized. It's a form of de-facto licensure that's easily recognized at a glancing distance, and serves to ensure that a mechanic is not going to leave on a moments notice, without at least bolting a wheel on. Instead, he or she will tell the foreman or whomever's name is on the sign, likely to call a tow truck for Friday.
It goes like this: Once a young apprentice lube tech graduates from Harbor F. University, an unusual ritual occurs in most mechanic's shops where a large, diesel, truck with a lift gate and a Square terminal approaches.
A nondescript individual emerges from the truck, (slowly, as to not alarm anybody who has a pending tab) where our young acolyte is soon taken gingerly by the hand and ushered onto this mysterious conveyance.
Seven or Eight hundred dollars later, the young, oily apprentice emerges holding a shiny, new, silver gun and possibly a ratchet and a t-shirt or pocket protector.
Most seasoned veterans will recognize this as their Mechanic's License. It's good for brake jobs, mostly.
If you foul up to many times in the shop, they call the MAC or Snap-On guy who will gun it in his diesel and demand full payment for the impact tool and ratchet. They usually get to keep the shirt though, because, yuck, you know?