Like the professor, I clipped many cars in the old days and was paid by insurance companys to do so. . Not only was this type of repair method understood as totally legal, but when done properly the result was a clean and much superior repair than fixing smashed areas....especially when rear clips. .
It wasn't uncommon when badge engineered cars became a half breed....like Novas w/ Acadian, Omega, Apollo or Ventura noses or rear clips. .
Section cuts, partial cowl cuts etc. were not as clean to do as a rear clip but never did we jump a Vin as it was always understood as totally illegal. .
To me this GNX # 298 job is an obvious felony and as much as the seller notes it has a collision history, his auction is completely misleading to an uneducated buyer. .
In cases where you can remove and reattach a Vin w/ the proper athorities present, I highly doubt jumping Vins from one car to another would be legit....anywhere! .
And good move James passing the thread onto the buyer....it may not make anyone happy but maybe it's not too late for him to understand what he's getting himself into? .

~ Pete