I tend to think, as with most things QF, the intent is a good one - and I don't subscribe to the conspiracy theory that it's just about protecting poor employees (more a side benefit or unintended consequence). QF is not the first airline in the world to specifically have such a policy and there are reasons. I also suspect there are less savory ones then filming a FA doing their job, but I'll leave that there.
As for the definition of public places and the law. This is such an interesting one to me, and no I'm no "bush lawyer" nor would I attempt to play one on TV because you know it's the vibe, it's Mabo, it's the constitution... no it's the vibe of the thing.....
I reckon it can be vague in certain situations, and there ARE examples of seemingly public places where photography/video is banned or at least heavily restricted for good reasons (think swimming pools, gyms etc). On the one hand, flying commercial is a form of public transport - one would consider the local bus or train to be a public place and have no consideration of privacy from general photography as on the beach, street etc...
OTOH, QF is a private company and they own (or at the very least operate) the aircraft you're being transported on. Now sure, the local bus or train is also likely operated by a private company who can assert conditions of carriage, but the reality is somewhat different I guess. Point being that QF can (and does) have conditions of carriage on their services (just as they can have a dress code at some of the domestic lounges - agree with it or not it's legal because the lounges are run by them and not a public place in the same sense that the terminal might be considered.
Is an aircraft cabin considered a public place? Are these rules enforceable? I think it's grey on the first point, and I can definitely see arguments on both sides. Enforceable? Well, if a crew member takes my phone - do I then have recourse about them "retaining" the device? If the answer to the first point is yes, then you'd think QF would be in a bit of trouble. Would it come to crew actually demanding to take a device off a passenger? I doubt it. There ma be some power trip types who would threaten it, but I think it's more a threat then an actual thing that would happen, but there as a warning - and as someone pointed up up thread for that person that wants to claim it's not in "the rules."
I honestly think that if push comes to shove on this kind of thing, forget the threats about devices and such, but it would come under the well known "failure to comply with crewmember instructions" - just about everyone knows that on an aircraft if you don't, well you can get into some big trouble - and that can be supported by federal regulations. Can that be a problem ? potentially.
At the end of the day though this really is one of those common sense things that you'd THINK people would follow as a matter of course (yes, it's the vibe of the thing imo). I mean someone deliberately filming or taking pictures of others without knowledge or consent is almost certainly not for a good reason - maybe harmless enough (ie: check out the person in the onesie in the lounge or gross bare feet on seats) - or less so. Where does filming crew if there are issues fall into this? unsure. Context is everything - just like the case of someone being pulled off a flight for being a drunken idiot or something - which as pointed out above will still be filmed (and I think in that sort of case nothing would happen to those that do so. it's just society these days).
The main thing is of course that these cameras and systems are not being deployed specifically at individuals or the like. That's quite different o someone choosing to use their device to target individuals (for whatever reasons).
