Possession of stolen property. If someone is transporting drugs and the response by the driver is "I don't know why my spare tire is full of cocaine" do you think LEO's just let them go?
Possession of drugs is illegal, possession of catalytic converters is not, not sure how you drew that comparison.
So “ I don’t know” or “do not answer questions” is a very appropriate response if questioned by the police. Unless of course you want to incriminate yourself. Police cannot impede your travels or your business simply because you possess an item that if frequently stolen.
But what is being proposed by some here would give them exactly that. And for what? Some measly cat converters?
What’s next? Checkpoints to make sure your cat converter is marked? If not, off to jail you go? Where does this silliness stop?