He also asked if this was my first O-A, which it is (acquired in my home country, previous years were retirement extensions from inside Thailand). Then he asked if I had entered the kingdom before. I think the whole insurance question was moot because I got the visa and entered the country before the 31st.
Buy a cheap exit ticket to a neighboring country. I think that there are even services that will allow you to buy a ticket for someone in your situation, but I have never used one. I'm sure that someone in this group will be popping up soon with a solution.
Forgot to add: The IO made small check marks next to my valid until date, category (O-A), number of entry (multiple) and the visa number. He did this in ink, directly on the visa. He probably did this in conjunction with taking the picture of the visa to prove he actually did confirm these items. He also added an "admitted" stamp on the opposite page, admitted until 28 Oct 2020.
Now, it's off to the Immigration Office today to check in.
Hey thanks! This is so helpful! I'm going back to LA (my home town) to get an O-A next month. The fewer surprises the better. Going to get my med cert here. I've allowed three weeks in the States, so I'll get on the background check as soon as I get there.