"Peter Duniho"
In the US, it's legal to fly IFR in Class G airspace
without the benefit of a flight plan or ATC clearance.

Really?... I guess it's time to break out the books and do some more
reading, I would have gotten that one wrong on a test. :-)

I'm having a hard time imagining a situation in which one MUST fly.

Actually, I was thinking of an incredible woman I met on vacation in Green
Turtle Cay, Bahamas this summer. She's in her 70's now, but in her day she
flew a Piper Aztec out of Treasure Cay. One of the stories she told was of
a woman going into labor that needed to be taken to a Nassau Hospital on an
IMC night. We sat there for several hours listening to this lady's stories.
There are some really interesting people in this world.

Dallas