Many people in Canada do this in the winter.
Warms up the car, helps melt ice and snow from the windshield, etc.
And if was on the man’s private property, what business is it for the authorities? Even if it was in a public parking lot, if he wants to risk the loss of the car, it’s his choice.
In Alaska we used head bolt heaters and plugged in the car when getting home at night. Apartment complex parking lots, etc., had poles with outlets on them and many could be toggled on and off from indoors if you didn’t want the electric on all night. It kept the engine warm which made everything warm up quickly in the a.m.
When my friend retired we asked where he was going to go. He said he would drive south until someone asked him what that plug was hanging out of the front of the car. He figured that would be a good place to retire.