Back in my early days as a VMS operator, the IT director once came down into Ops central, marched onto the machine floor and boldly flipped the Big Red Switch that switched the power off to the entire data floor.
Cue clenched sphincters as we waited (and waited ... and waited) for the backup generators to kick in before the UPS died. Then they marched out and simply said, "We've had a power failure. Call DEC and put the disaster recovery plan into action."
This was, apparently their way of conducting a full resilience test - no, DEC had not been pre-informed of the test either - as far as they were aware, it was a genuine disaster - and the recovery plan involved them trucking in duplicate hardware for all our key machines on what was effectively a mobile data centre. Must have cost [i]someone[/i] a hell of a lot of cash to put that thing into mobilisation.