We had a version of this at college where if you left a computer logged in (this was the days before everyone had their own device) then you would send an email to the dean of the school making some or other outrageous request and cc'ing the whole school year mailing list. They were pretty funny!

Another workplace had a similar scheme: an unlocked machine was an invitation for the person's neighbors to send email on the person's behalf. It was all fun and games for a while (fake product announcements, silly questions posed on the internal mailing alias, fake resignation notices) until someone got really upset when it happened to them and then it sort of died down.

We do this at my office, but without email, if someone leaves their computer unlocked, we're allowed to give them a gentle reminder not to do it in the form of a new desktop wallpaper or reversing their mouse keys and/or scroll direction.

It supposedly was the tradition at Intel to, on finding a unlocked desktop, to fire up Outlook and send a message just reading "I love you" to the person's manager.

I don't know if this really happened.

Boss at my old company was hot on making people lock their machines. Used to leave notepad windows open saying "lock it" or similar, even when we had just gone to the other side of the room and could see him doing it.

After the Nth time of him being hypocritical and leaving his own machine unlocked when he went out of the room I made a scheduled event that popped up with "update complete, rebooting" and then restarted his machine, set to run randomly once a day between 9-5.

We did this, but to all of IT professing their love for all to see.

At my current company, it's an email to the team promising to bring in for donuts or pastries friday morning.

People rarely leave their machines unlocked anymore :)

Leaving your computer unlocked is a great way to discover you'd sent an email offering to buy lunch for everyone in the department.

I see you Google ;)