Cleaning desks? Pah, I can beat that!
Working for a well-known (mostly? almost? not sure now but I think it still was back then!) British company in the 90s and we started getting rather angry calls from our Users complaining that some of their computers wouldn't reboot.
We had a couple of our on-site hardware engineers (the youngest pair, let's call them "Tweedledum" and "Tweedledee") that had been PAT-trained as none of the other (older, more experienced) engineers wanted to do it.
"That's okay," says the Boss, "We have a couple of hardware engineers over there doing PAT testing, we'll get them to pop up and take a look."
Some of you will have noticed I said "reboot" and "PAT testing" and worked out what had gone wrong. Or, rather, who. Sure enough, when the Boss tracked down The Thickie Twins it turned out it hadn't actually occurred to them that they should shut down the computers properly before yanking out the mains leads and connecting up the PAT tester... or even, on some of the desks, to actually plug the things back in before walking off to the next one...
(On a slightly related note, Site Services had done the testing for stuff like kettles, desk lamps etc - Tweedledum and Tweedeledee were "just" doing all the IT kit. Except they forgot that included things like printers, scanners, routers/switches... Strangely, a couple of the other engineers got trained up to do the 'catch-up' stuff. I sometimes wonder if it might have been one of the 'customer' team managers threatening bodily dismemberment for Tweedledum and Tweedledee, and whoever sent them back over that inspired that..?)