The FCC interference requirements are designed to prevent your usage from interfering with others. It's perfectly acceptable to interfere with radio signals for yourself. Anyone who grew up in the 90's and had a car without a built in CD player has used an FM-transmitter to broadcast the audio of a portable CD player to their radio, interfering with any other FM signals on that frequency, albeit in a very small area around the car.
Still useful today. I still use an Avantree (https://avantree.com/collections/bluetooth-transmitters-rece...) on my visor everyday to broadcast from my bluetooth phone to my early 2000's vehicles with "vintage" AM/FM/CD stereos that I think are really cool and I'm quite unwilling to downgrade just to get bluetooth.
