That was an old IBM Mainframe joke - HCF = "Halt and Catch Fire". Sad part, on those primitive mainframes there WERE really easy ways to sabotage the whole system remotely, or in ways you never thought of.
There were ways to shut down sub-systems remotely - then the crude regulated power supplies with no load would try to sink the excess power into Zeners or early switching transistors, and could indeed overheat and catch fire.
Like having the Power Dump emergency shutdown button under the console where you could hit it with your knee - needless to say, that didn't last long. They moved it and guarded it with a flip cover, and most places put a note on the cover to the effect of "Is pushing this button worth getting fired?"
And the open reel tape drives with optical stack and EOT sensors - someone takes a flash picture or two in the server room, and suddenly all the drives are spooling fountains of 9-track mag tape all over the floors...