I remember standing these long boring LORAN control watches in the USCG when all of a sudden things would go haywire. X-class flares. I would have a web page pulled up to USNA space weather at all times and the LORAN symptoms always happened before it would even show up on the satalite data. We had a special phone number for each other, they were supposed to call US for space weather alerts. Sometimes I would see the symptoms and call them and say "an X class is about to happen", was pretty funny....memories. I'm sure that is one of the few jobs in the world where people actualy worry about solar flares.
Oh, I don't know about that. Comm Sat companies. Users of those services. Extremely paranoid users that might rely on them for backup, since fiber does get cut, lasers die ...
I think the first recorded solar flare affecting society was in the 19th century. One actually drove the telegraph system haywire.
Oh, and I wonder if last Fall's flares took out the Jap Mars mission? One or two months shy of two year trip and the
thing dies from a solar flare. They probably worry about solar flares. At least now they do.