But that's 95% of cars that didn't need to be tested. All that the testing requirement does is reinforce the (correct) public's perception that it's a free money scheme. If the "check engine" light is not on in a modern car it's pretty much good to go.

When cars do need an emissions related fix, it's almost always that little charcoal canister that people flood with gas because nobody told them why it's a bad idea to top off the tank after the first click.