During the first days of during Operation Iraqi Liberation once embedded "journalists" were on the ground, chemical weapon sirens would go off daily. Broadcast around the world were reporters stopping live feeds and quickly changing into hazmat-like suits...
We now know there were zero chemical weapons, so why so many alarms?
"In all, American troops secretly reported finding roughly 5,000 chemical warheads, shells or aviation bombs, according to interviews with dozens of participants, Iraqi and American officials, and heavily redacted intelligence documents obtained under the Freedom of Information Act."
http://www.nytimes.com/interactive/2014/10/14/world/middleea...
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"According to the 10,000-word, eight-part interactive report ("The Secret Casualties of Iraq's Abandoned Chemical Weapons" [by the NY Times]) by C.J. Chivers published on the paper's website late Tuesday, at least 17 American service members and seven Iraqi police officers were exposed to nerve or mustard agents in Iraq after 2003."
"'Nothing of significance’ is what I was ordered to say,” Jarrod Lampier, a retired Army major, said of the 2006 discovery of 2,400 nerve-agent rockets at a former Republican Guard compound, the largest chemical weapons discovery of the war."
https://www.yahoo.com/news/chemical-weapons-found-in-iraq-ny...
The cost of a false negative when lives are at stake are worth noisy alarms (smoke detectors).
Anecdote: Yes, errant gun fire and far off explosions stopped making the hair on the back of our neck stand up during deployment, but we always waited for the controlled detonation signal or confirmation if the area where small arms fire was happening. It's possible that my perspective didn't match the general sentiment of the unit. It still seemed like there wasn't much complacency.
And one of the times where the explosions weren't controlled detonations, the reaction force was mounted and moving to location in the standard allotted time.
But a steady stream of elected officials have come out and declared that this is clearly and unquestionably an attack by the Russian government. Most of the news stories went out of their way to connect the attack to Grizzly Steppe, strongly implying that it wasn't just raising alert levels but exactly matched the discovered malware.
Your summary is a good one on how these things happen naturally, but I'm seeing a healthy dose of direct provocation in this panic.
We can't be sure who the attacker was, or their ultimate goal. It could be a random event, some piece of automatically distributed malware, or part of a targeted attack.
This sort of false alarm is normal after an attack. Attention levels go up, events that look like possible threats are detected and have to be investigated. Go back and look at the aftermath of 9/11. There were false alarms for months. Further back, see the Battle of Los Angeles in 1942.[1]
Remain watchful; do not panic.
[1] https://en.wikipedia.org/wiki/Battle_of_Los_Angeles