As the originator of this thread I fear that the discussion has moved away
from the original question which was the appropriate concert etiquette I
as an audience member should adopt during a performance of 4'33".

It seems to me that disappearing out to the snack bar or rest room means
that I cannot claim to have heard the performance.  It therefore seems
essential that I remain in the concert hall.

Is it OK for me to turn the radio on to catch up on the football scores
during a performance?

Or perhaps even more pertinent, is it OK for me to go up on stage and
knock out on the piano a few choruses of, say, "Roll Out the Barrel" during
4'33"? Would this violate anything? Remember I am part of the audience and
not one of the concert performers.

Best wishes,
Gordon Henshaw