I'm sure that 999 times out of 1000, the state isn't going to pursue a legitimate machine shop because in the course of rebuilding an engine the block is decked and the original ID is restamped. Just like the trim tag issue, they simply don't have the time, expertise, or resouces to investigate and look at every tag.
Other statues do give law enforcement the authority to visit any type of body or other repair shop and physically inspect cars there but, again I assume, it'd be done in the course of an overall investigation and not just on a whim. The new statute gives them some teeth to charge and/or prosecute if they find suspicious activity. Like selling VIN rivets, if they find some persons selling trim tags at $250 each as 'collector items', they may get busted as well.
It also gives the buyer of a high-dollar restoration of any car some protection against not only altered VINs to represent that high-dollar car but altering or changing trim tags as may show a car as one would like it to be instead of what it was before a restoration some added assurance...not much, but some.
Personally I think the trim tag issue may be hard to enforce, especially for items like trim and paint. If there's no history of the information on the trim tag being recorded, if a white car with blue bench seat interior and Powerglide transmission is completely stripped and painted red and retrofitted with black bucket seats, console and a 4-speed, who would know? Unless one could prove the 'new' trim tag that says it's a red/black/4-speed car is from another vehicle, I think it'd be quite difficult to prove.
Anyway, like it or don't like it, care or don't care, it's interesting to discuss.