I've done a lot of (very) fast road drives in groups with this sort of thing going on. I'd rather be on my own, frankly. People make mistakes, bad calls, badly timed calls etc. Unless you're absolutely willing to trust your and some potential random 3rd party's life to that radio call, you should treat every overtake as if the radio didn't exist.
That might be different if you're in a group of people who you absolutely trust completely and have done many thousands of miles as just that group, but in general I won't trust it.