I think you're right frisbee. Its like the non smoking rules. The government says its happening, and its then a rule of carriage into that country.
Id be more concerned with the quality of air marshall Id receive on my flight. Having walked past most of the "CHUBBy" security provided at SYD (QF)showing a pack of winfield blue as ID....what hope have you got against a real threat????
The pointy end crew should have the option to carry weapons, and the FSD should also have access to a weapon. This also takes away the confusion caused when people (air marshalls) in civilian clothing jump out of their seat...you cant tell them from the threat!!! If the staff with weapons are in uniform, then its easier to say everyone else with a weapon is a threat.
Then again, proper security at checkin and a cockpit door not made of laminate would alleviate the risk far more.
The question must be asked....how many pointy end crew WOULD carry a firearm if allowed?????