The New York blackout of 1965(?) (I was in the affected area) was mostly a novelty, and people were largely civil about it. The repeat in 1977 turned nasty in several spots, with looting and violence breaking out.

Then there was the great "Montreal" blackout- January 5-February 8, 1998
Duration: Up to 33 days in some areas.
Geographic area: Four provinces in eastern Canada; four states in the northeastern US.
People affected: 5.2 million.
Cost: Combined insurance losses in Canada and US exceeded $1.2
billion.
Cause: Ice storms took out more than 1,000 major transmission towers and 35,000 wooden utility poles.
Effects: The storms were directly responsible for 45 deaths; 100,000 Canadians were forced to take refuge in shelters.

During that period, people who started emergency generators routinely had them stolen within hours.

My parents went through the Connecticut "Ice Storm" in .. 1977? Power was out for a week in their area with sub-freezing temperatures. At first, no one could get out, because the streets were covered with glare ice. Later, most people left the area- it was not that far to hotels and motels with power. My parents and my little brother stuck it out- some of the houses that had been deserted had been robbed when the owners returned.

They closed down the whole house except for one room with a fireplace. My father drained the entire water system to keep the pipes from freezing and bursting- it turned out that the owners of one nearby house were away on vacation, and they had over 100 pipe breaks and huge flooding damage when they returned. Other houses were crushed by trees, toppled by the weight of the encasing ice.

My parent's house had it's own artesian well for water supply, with an electric pump, of course, but they were lucky... there was enough natural pressure to fill buckets in the basement, so they had water for cooking, drinking, limited washing, and, most importantly, for flushing toilets.

They (my mother) cooked all of their food for a week in the fireplace, using a decorative popcorn popper. My father had a great deal of wood laid in, but it hadn't been split yet- he said it took 8 hours of splitting wood with wedges and sledgehammer to keep the inefficient, mostly-for-show fireplace going for 24 hours. They banked the fire as best they could for the night, and slept together in a sleep-sofa under piles of comforters for warmth.

I would have guessed that my parents were among the least likely people on Earth to do this sort of thing- I doubt that my mother has spent a night outdoors in her life.

Anyway, bottom line, yes, blackouts can be very serious. It all depends on how widespread it is, and how long it goes on.... and the weather. Because of my limited experience with them and my parent's much more extensive experience, I'm pretty well prepared for blackouts these days- which means, of course, that I've never really needed the preparations.

My father later bought a generator, and an efficient wood stove, and some other items that would have been very handy... but in the end, they moved further South. They had other reasons for that, but I doubt that the experience was ever entirely out of their minds during the decision process.