I've personally heard a Stingray being used for an arrest being broadcast on an open, analog channel.
https://youtu.be/re9nG81Vft8 (Can't find the original.)
Apparently they didn't know about MTDMon software. Which was even cooler than listening on a scanner, because you could set it to beep the PC speaker if your keywords appeared in the feed.
I assume all that is encrypted now, but it sure wasn't at the time!