Haha, had the same in my last place.
At another place I worked, the devs took a screenshot of their desktop and made it the lock screen image, so it looked like it was unlocked, just to annoy security (i.e. me!).
At another place I worked, the devs took a screenshot of their desktop and made it the lock screen image, so it looked like it was unlocked, just to annoy security (i.e. me!).
Overall the "buy treats for the office" rule helped to establish the habit even though I think we never followed through with it. We mostly just told newcomers that this is the rule and they locked their screen as expected. And ofc it turned "Hey, lock your screen!" into "Oh, you want to treat us?" which makes for a more cheerful way to remind people.