Why is this so hard for some people to understand about commercial license plates on their vehicle?

I have stopped many people that deliver pizzas. the only violation they are committing is the registration law. in my state, if you use your personal vehicle for business, you have to have a commercial license plate attached to your vehicle. many of the pizza delivery people could never understand this, since they use their own vehicle to deliver pizza. ” why can’t we keep our personalized license plate, instead of a commercial tag?” they asked. bottomline, it is a violation of registration in my state and they want the revenue. also, if the driver is involved in an auto accident, his personal auto insurance may cancel, if he did not notify them that his vehicle was being used to deliver pizza. so, is it really worth it to deliver pizza in your own vehicle?