I once called the FAA to report a whooper on 121.50. It apparently was coming from a plane in motion. I told them what time I heard it the loudest, and my location. They seemed to be grateful for the info. I think they were already aware of the situation before I called, so I was just adding some supplemental info.
I also called the US Coast Guard in Boston once. I think that someone was horsing around on Marine Ch 16 near me. I remember they asked me if I had any DF equipment, but I didnt. He seemed to be appreciative of the call also.
Recently I heard Boston Fire trying to find a ride for a disabled person. The dispatcher said he couldnt get in touch with the paratransit service. I called up the paratransit service directly, told the dispatcher the story, and she said she would call Boston Fire. About 10 minutes Boston Fire Alarm was telling Ladder 26 that a van would arrive in 10 minutes. By that time the party was already on his way.
A long, long time ago - when I was young and much much more foolish, I called Boston CMED and told them they had a gunshot wound victim going to Mass General Hospital. The ambulance, which I think was coming from Revere or Everett, was trying to hail Boston CMED on 155.28 or 155.34 or 155.16 - ancient history here - maybe the 1970s.
I try to keep in mind that jumping into a high stress situation when you have the slimmest of info to contribute can be a dicey proposition. Sometimes it is the right thing to do. Maybe sometimes it is not. If you start off by giving your full name, and telling them that you are listening on a scanner, they might appreciate the honesty up front - and make a quick judgement of the value of your info.
Another one came to mind - no two of them - there was the time that BFD had 2 repeaters up and running on Channel 2 - I called BFD Fire Alarm and told them about it - they seemed to be thankful for the call but wanted to know who I was IIRC - I just told them I had been listening to them for 20 years. Now I remember - one of the companys had forgot to turn off a inhouse repeater at a call they had been to previously in some highrise or large bld.
And the time the Newton cop missed the call for the needle on the sidewalk. First thing the Newton dispatcher said to me - "Did you put it there?" - I said "no" - he got over it real quick - and redispatched the call.
And the beat goes on.