I would assume if state law says X, and you are in violation of X, it only takes the right officer to nail you for it. The law is against you in this case, it sounds like. Probably don't hassle people for it most of the time because it's pretty hard to prove that a random individual isn't going to a car show, or whatever else the law might allow for that type of plate in your state. But if the same officer sees you driving to/from work or school every week?
But look at the actual law for your state...in WA it's to and from car shows, tuning, and something along the lines of "benefit to others". As I said in another post on this same topic, IMO every time I drive the truck it's tuning, and that's truthful. I wonder if this is one of the reasons that there are so many "car shows" arranged, so that people can say they are going to or from said car show, in case they get pulled over. In the summer, it's impossible to go more than 50 miles without there being some sort of car show.
At some point, if abuse gets out of control, people who use the plates improperly will get things changed. Already been TV station "investigations" about people abusing the plates here, so it's probably just a matter of time before the few ruin it for the many. My excuse of always tuning, while technically true, is probably outside the intent of the law.