Gremlin
If you are further than three miles from an airport the 400 ft limit does not apply and if the airport operator gives permission you can fly higher than 400 ft right on the airport.
He was talking about AC91-57, not AMA SC and the
Infamous Comma.
What this has to do with the thread
is that I was correcting his mistaken belief that AC91-57 compliance was mandatory,
(AC91-57 required proving flight before flying with spectators)
just as I am now correcting your mistaken belief that AC91-57 has the
AMA Infamous Comma limiting the area of the 400' cap.