Ran into the same thing on a job in Tulsa back in 09, guy next to me flipped his level and watched his whole wall walk. Bubble wins every time for me because string lines sag and get bumped. Level does not lie unless you are holding it wrong.

Keeping backups of your own stuff is smart, but treating every screenshot like legal proof is where it falls apart. Both sides in that mess you watched were editing shots, right? People crop, people fake timestamps, people screenshot their own DMs after deleting the parts that make them look bad. A drive full of your own posts only proves what you saved, not what actually happened. Where it helps is when someone twists your words and you can pull up the original in two seconds instead of arguing from memory. That's worth doing, just don't kid yourself that it settles anything with a mob.