Having been in a situation where I had to emergency shutdown a (small) data-center in an office building, the person doing this is not necessarily an electrician or someone who knows where the breakers are, and if they do find them, if it's safe to mess around with them. Unplugging stuff is well understood and less likely to cause other problems.

Put another way:

- I unplugged a power cord => Reasonable

- I pressed some buttons on an electrical panel without really knowing what I'm doing => Unreasonable