How many plates required?

The reasoning behind this is some people would have 2 identical trucks, pay once in a jurisdiction that issues 2 for front and back, then just put it on the front of each truck and copy the cab card. Here in ontario the cab card is now just a print out. It could be photocopied without a problem. Only a close eye of an inspector may notice the vin does not match the copied cab card should the duplicate truck get inspected. Heck you could even manipulate the vin for our cab card. I think they look it up in the system when they do an inspection to see if it's real. I'm not sure if an inspection in the usa would be able to access our system to match plate to vin. That is why a lot of jurisdictions only give out 1.