What’s stopping another person/company from transmitting on the same radio frequency as an established radio channel?

Question

What’s stopping another person/company from transmitting on the same radio frequency as an established radio channel?

In: Technology

Answer 1

Before Bluetooth and headphones jacks became common they had ipod or phone adapters for cars that would broadcast in the FM frequency range so you’d just tune into your own broadcast frequency on the car radio.
They are legal since they are very low power.