Might be "somename" is correct, but for me it feels just wrong to unplug a hot miner knowing that the hot air from the chips gets more or less stuck in the miner for a much longer time when the air cirulation stops.
The heat does not increase it decreases slowly.
Lets say temp inside was 70c all power cut. Temps go lower slowly nothing wrong with that.
Temps dont rise there is no energy being sent to gear.
If unit can run 24/7/365 at 70c it can take three hours to cool from 70c to whatever,
Your fear is not logical or rational.
And the suggestion given that you can turn off internet whic will stop hash but let fans run is simply not needed to do.
As cooling the gear down from 70c to say 20c in ten minutes is harder on the gear then taking three hours.