Silent
You seem to think there is something unusual about "voluntary" compliance. Why? Most laws, rules, and regulations rely on voluntary compliance. Nobody stops you from speeding, from robbing a bank and so on.
You are comparing apples and volkswagons.
The difference is in whether the enforcement of such a compliance incurs penalty or not,
in that the rule itself does or does not allow noncompliance.
AC91-57 asks for voluntary compliance with no penalty for non-compliance.
AMAs stand on fed regulations seems to ask for voluntary compliance with no AMA penalty for non-compliance.
Where as your example of voluntary compliance of
'speeding, from robbing a bank and so on' DOES incur penalty for noncompliance. Same with my earlier example of tax evasion and murder, there is severe penalty for chooseing not to comply and no builty in 'I choose not to comply' exemption from that penalty like the AC and AMA have
So when a guy says he will comply with the voluntary nature of AC91-57
and fly at thousands of feet above the
400'EverywhereAlways because the AC is voluntary compliance rule,
do you see that as the same as
a guy saying he will not comply with a 100mph fed speed limit and just hope he is not caught and punished for failing to comply?
When a guy says he will obey the AMA
that dont mean he wont rob a bank: Cause the AMA dont have a rule against bank robbin.
Just as AMA looks like it wont be enforcing some other laws, like say the ones in that FAQ that was cited.
So just saying one will obey the AMA dont mean they will be obeying the Fed all the time
(I point to WestcoastFlyer for reference)