It works the other way round, too. Weeks prior to the Russian attack we saw a multitude of videos from Russia and Belarus, trains moving equipment from far east as an example. Those videos revealed missiles in open top carts, T72's of the first build, ZIL trucks, they showed the lack of modern equipment. We saw videos of Alligators and hinds moving closer to Ukrainian borders. The social media actually gave a pretty good idea what is being gathered against Ukraine. And those are the goods that has been seen on the field. Additionally we've seen people analyze the goods Russians have been hauling towards Ukraine throughout the war, a certain video showing airborne armor being moved by train to Belarus comes to mind.
All this has been discussed in this forum in lengthy threads. Has this discussion been giving out any new insight to the authorities in Ukraine? Has it been of use to the western intelligence? I very much doubt it, I reckon they knew it before we did.
And to make it absolutely clear, I am very much pro OpSec. But would the discussion on Pprune about info freely available on internet really fit in that bill...