Ring true with anyone? Well, yes, of course...
At my last company I had something of a reputation for aggressively policing unlocked screens, but when I was back there last year I was amused to see that it had evolved into "Free beer at XXXX's desk" messages sent from the desktops of (usually new) staff who left their screen unlocked.
That policy worked incredibly well, because the people who knew just quietly snickered, but the people who didn't would turn up and get educated - a very nicely targeted message.