Even in D, E, and G? 91.215 only references class A, B, and C airspace
and I was under the impression (instructor and the Cessna Cleared for
Takeoff book) that unless you were within those areas (or within the
veil outside of the B) that transponder use was optional.

You're right. I misread the FAR.

Whew! Man, George, I thought I was losing my mind for a minute there.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"