It is true. One evening I flipped on my radio and was listening to the police repeater. Some dude called in worried about his wife, didn't know where she was. The dispatcher sent in a request to "ping" her phone and in less than 5 minutes they had all the info they needed for her last position. I was actually shocked how fast it went down.

Truthfully you have two options - keep it off, or leave it on and put it in airplane mode & w/ no gps. Even then I dunno if the radio is totally shut down.