In a commercial vehicle with a plate violation, that means the driver would be the one responsible not the employer.
I used to drive a box truck decades ago making local deliveries. I would have been pissed to get a ticket and fined for something my employer did considering I was making only $4 per hour
I'm an owner/operator, so in my case, it would be me getting the ticket, not sure what the law is on company trucks, I've never drove for a trucking company unless you count my company.
I thought speeding was considered a moving violation with fines and points while a plate violation is considered an equipment violation with no points.
You are correct, however, if I get pulled over because of an equipment violation, I can be shut down until I get the problem fixed and inspected by either Fed. or State DOT, if it's something like unregistered vehicle, fictitious plates, no insurance, they can tow the vehicle and it would cost a ton of money in towing and storage fees along with the legal fees involved.