Valuable metals like rhodium, platinum, and palladium are used in anti-pollution parts of cars. Parts that are hard to track down are easy to cut off a car, which makes them a good target for people who want to make money quickly at a scrap yard.
With the two new laws, buyers will have to pay more if they can't prove that a catalytic converter wasn't stolen. This should make it harder for thieves to sell stolen car parts.