Has anyone ever tried just saying "no" to an unsolicited offer of a friendly chat with HR to avoid getting fired? I think it would work.
Annecdotally, yes. Sort of.
to tl;dr:
Background: a friend worked at a start up that got bought out. Everyone knew what was coming eventually because they knew they were bought for one or two aspects of their business + patents, not to continue pushing thier product. (but everyone not utterly retarded had their stock options go to the fucking moon so most converstations post-buy out were what they were going to do with their fat sack of cash once they were fired.)
So one day my friend hears a bunch of people's outlooks going off with "New meeting invite has arrived" notifications, and figures its the day everyone is getting fucked and doesn't feel a need to get fucked in person, so just shuts down their shit, grabs their box of personal items they want to save (as well as whatever tech items they intended to keep as "bonus severance") and heads home; no need to stick around and fight traffic, becasue what are they going to do, fire him?
Anyway, about 10 minutes after the meeting time his phone rings, its HR asking if he was attending the meeting, he said he was out of the office today. They said thank you and ended the call. He came back in the next day to see if his badge would still work, it did. His account wasn't locked out. he sees the meeting he skipped was canceled and removed from his calendar.
After some whispering, he got the skinny. Corpo HR had been told to fire a certain number of people from the Startup. They had a list, and just worked down the list until they hit that number and then stopped having meetings and canceled any remaining meetings. He worked there for just shy of another year until they fired him and all the other employees who were still there.
I also knew a guy where there was another mass firing even, he was legit out sick that day. It took HR until the next month before they realized he (and a few others) had been missed.
So in conclusion, it sometimes DOES work, just usually not for very long.