What is right?

That depends on what State your "friend" lives in. In Georgia, you could transfer the plates to the car at the Tax collection office, who handles vehicle plates.

And this is from the licensing site in Idaho, where I live now.:

The license plates you display on your personal vehicle belong to you.* When you sell or

otherwise transfer a vehicle, you need to take the plates off of the vehicle. That way, law

enforcement officers will not assume the vehicle is yours when they pull it over. When you

keep your plates, you can use them on another vehicle you may acquire rather than having

to buy new ones and receive credit for any remaining time on your registration.

You will have to check with the DMV wherever in the world you are. In the states I believe California is the only state where plates stay with the vehicle. In other states the plates belong to the owner and car plates can be transferred to another vehicle that uses car plates, or truck plates can be transferred to another truck. But usually truck plates cannot be transferred to something that uses car plates.

For example when I traded in my pickup truck for a Pathfinder (SUV) I had to get different plates for the SUV (which I guess is considered a station wagon). And when I traded the Pathfinder for a Subaru Outback, I was able to transfer the car plates to it.

he can not.

Even if your state would permit him to transfer the same plates from one car to another, he would still need to fill out paperwork to accomplish this legally. He can't just decide to do it of his own accord, undocumented, and hope for the best. Your friend isn't very bright, is he?

Nope. Plates are registered to specific vehicles.