Los Angeles is is considering letting people who take public transit to the airport have priority security. This isn’t PreCheck or CLEAR, just priority line access for the regular security queue, and follows a program at Boston Logan for people who take a shuttle bus or ferry to the airport.
Priority security isn’t actually free, in other words it isn’t costless. “When everybody’s priority, nobody is.” Grant everyone priority and they’re behind everyone else who is also priority that got there first.