Is this riveted ground wire part of a UL approved factory assembly?
Factory assemblies can't use pop-rivets either. If you look carefully at a factory riveted ground, you'll see that it's either steel or brass, and uses impact assembly instead of a "pop" pin. Pop-rivets are too soft to be considered reliable connectors. They're also generally aluminum, so you couldn't count on good electrical connectivity unless you gooped them with anti-ox.