A couple thoughts:
Regarding giving out info that’s not classified, assuming that someone who has been out of the business still gets the newsletter informing everybody of which info is still classified (and when all the secret brunches are held at the E-Club), there is a thing called “Operational Security” (or OPSEC because we love abbreviations and acronyms in the military). Basically, don’t give out “unclassified but sensitive” info.
When I was in tech school, the barber shops were set up so that we’d be staring at a poster showing some person’s villainous hand reaching into a trashcan for a wadded up piece of paper with the message “YOUR GARBAGE IS THEIR TREASURE!” I always wondered what the barbers thought about that. Every now and then, you’ll see a “LOOSE LIPS MAY SINK SHIPS” poster for nostalgic value or a parody of one in someone’s cubicle.
As far as the Russian trawlers go… I have read stories about how the RCAF would pass the time by harassing those guys by making low passes at them with patrol bombers. Supposedly they had an old prop-driven bomber based on a WWII plane that would generate sufficient prop wash in a low-altitude high-speed pass to “accidentally” snap all of the antenna off of one of those things. Then they’d fly by again, slower, and give them a friendly wave.