I feel the real danger of back feeding is not that american line workers can't be bothered to check if the line is truly dead before starting to work. It's that the line could be reenergized at any time.
Automatic transfer switches are a thing, but generally you want the supplies sync’ed.
A manual break-before-make transfer switch will do the job. Not much help if you’re not home and the mains goes out and your food spoils, though fridges will stay cold for hours if left shut, and longer if there’s a lot of thermal mass in them - try to keep most of the empty space in your fridge and freezer filled with water bottles.
I haven't seen them doing that on power outage post storm line repairs near me, usually during those they're working as fast as possible because they have dozens of other spots they need to repair.
Also just the frequency with which work happens on the distribution grid. Most of Europe has almost all distribution lines underground (only running high-voltage transmission lines above ground), and unless somebody digs in the wrong spot they tend to just stay there. In the US meanwhile they are mostly above ground where they are susceptible to storms, falling trees, aluminum ladders and all kinds of other stuff that would cause a line worker to be called out
