n the United States, an "open carrier" ( also known as a "open microphone", "keyed microphone", or "open radio") is police parlance for a radio that has been inadvertently left on in Talk/Transmit mode. An open carrier stalls and paralyses broadcast traffic, leaving so-called "dead air" to reveal sudden gaps, smudges of hiss, gently swaying drones, beeping alerts, fragmented words, quick phrases, recessed conversations, and other unexpected artifacts. It's like butt-dialing everyone who is listening to the radio.
Multiple times in the series officer Grant asks someone if they have a license for their gun. The state of California does not require a license to purchase or own guns, only a background check.