A popular bill will force car companies to put AM radios in vehicles at no extra charge, despite decreasing interest from drivers and potential electromagnetic interference.
Nothing, other than that there's no possible way that'd actually be cheaper than just including it in the godawful-complicated touch screen entertainment center that will pathologically already exist in every new car.
Then you severely underestimate the FCC and the amateur radio community. They might not find them immediately, but they will find them. People get tracked down for a lot less than fake emergency broadcasts.