To put some things in perspective from the other end of the radio...
Guys on the street, (depending on location) - really don't care or have the time to eavesdrop on other jurisdictions. For decades, agencies (regardless of function) operated on various radio bands and methods.
When I got my start, lowband was used by the state, we were on UHF and PD across the way was VHF. Town fire was lowband and UHF, EMS on VHF.
When the 800 system came out, the state went there, one town went LTR, etc.
Do you know how much of an issue it was for me to communicate to neighboring towns or the state for resources?
It wasn't.
It was a simple call on the phone or radio to radio link on a common analog radio channel (regional or statewide)
Accurate and timely information was never a problem, and helped to filter unnecessary information to the responding resources.
Life is much different on the radio on our side than on the scanner listeners side.
On scene, most departments can and do utilize their on incident channels. Not everyone needs to be on the same channel/talkgroup. That's what the unified incident command system is for. Not everyone needs to talk to the IC - and when everyone is operating on a single channel/talkgroup with various resources - that's when situations happen and things go south.
Now within a single agency incident - the above can and usually does happen. FDNY does an excellent job of this. To the causal listener, it seems like complete and utter chaos. For the members operating on at the scene, its not. Trust me it can be, but when you operate and train the same way - its SOP. See this example:
https://www.youtube.com/watch?v=O0O68VS3Axw
Just not a multiagency/large/MCI incident. This is were IC discipline comes into play. Some are better at it than others.
As far as on air incidents/cover ups go - that's basically urban legends. I've never seen or been apart of, or aware of a time where over the radio, Joe Cop was telling his buddies that he just planted meth on Bob Badboy, shot the wrong person, or the such. Could it have happen? Always a possibility, especially when phone patches were available and people thought conversations were private.
But that day is essentially dead.
Public safety is well aware of scanners, and scanner apps. Social media persons (good/bad/indifferent intent) have recorded/transcribed and taken over the air information and purposely twisted or improperly conveyed the what was heard and caused harm in active investigations and safety.
I am personally aware of an incident in which a multiagency operation was going out to serve a search warrant at a narcotics lab. Everyone was to use a certain talkgroup that was secure. Prior to the operation, two town cops used a non-secure tac channel to coordinate coffee orders and essentially "hey before we go over to 123 Main street what do you want from dunkin donuts".
Bad guy heard that on his scanner app, left the property before they got there - and even left a note that said "better luck next time guys" on the front door. When he was caught later, that was all admitted.
OPSEC is something that some cops work well with, and others are just plain oops. With ENC options being so cheap these days and with no voice quality issues that SECURENET had, its hard for any chief to say "why not?"
When one of my agencies went to P25 (prior to P25 scanners), they offered every new agency the option to purchase a radio with certain talkgroups programmed into it so they could report the news.
If one feels as though your local agency running ENC is such an issue, as someone above did - contact your town elders, present a good solid argument (do use "well its my hobby and I have to listen to it" argument) - but something factual and can stand on its own - weighing the pro's and con's of all involved.
If they still decline, reach out to the government sunshine groups and state elected represent ivies and push the issue, and get as many people (who can form a good argument and not take other less than idea routes because they are pissed) onboard with it. I believe there was a rep in CO that was looking to introduce legislation limiting ENC for public safety, but I don't know the status of it.
In any case, radio comms are typically part of the open records act, and you can do a FOI request for the such, paying any reasonable expenses allowed by law for them to reproduce the radio transmissions. Of course anything that is subject to an active investigation and ongoing criminal prosecution would normally be exempt until the court case is finished or publically released.