"Michael Houghton" wrote in message
...

My bad. Your postulate was invalid. "November 1234, radar contact."
is not an instruction. It does, however, "establish two-way radio
communication" which authorizes entry into Class C airspace.


Negative. Communications are established only once per flight, that was
done with the first communications exchange.



Entry into Class C airspace does not require affirmative instructions,
unlike Class B airspace which requires an affirmative clearance.
If ATC wants you to remain clear, they have to keep saying so if they
are going to communicate using your tail number.


No. ATC only has to issue any given instruction once. It remains in effect
until overridden by another instruction or the original request is dropped.