Unfortunately, I had to go to a funeral on Monday morning. They had two lines of cars in the parking lot - one for people who were attending only the service and the other for those going to the cemetery for the burial. I was in the latter line. 

One thing they told us to do at the end of the service was to tune the radio to 96.5 FM to hear further instructions, about when to leave, where we were going and other protocols. I did and sure enough, there was a signal there. I suspect it was carrier current because once we drove out of the parking lot, it disappeared. 

I know occasionally a home for sale will urge interested buyers to tune into a blank frequency to learn details of the house, and it fades as soon as you drive away, although I haven't seen this in use for a long time now that there's Internet and smart phones.  

My questions: do they need any kind of licence for this extremely limited range? How did they pick the frequency? And is this a common practice?