Sinala,
My understanding and experience of the European situation is that anything bought airside (not just booze at the duty-free) can be carried on board; it's the taking stuff into the sterile area that they're getting at. So if you nip into the term and grab a 375ml Coke, you'd be fine - at least you would be at Heathrow.
Topend,
hundreds of regional ports in australia that handle jet services
I didn't think there were 'hundreds' of such ports in Aus?!
Plainmaker,
I'd been having similar thoughts; I recall some years ago, when certain amphetamines were hitting the club scene and there were reports about punters dehydrating, grumbles about nightclubs only providing hot water out of the taps and charging silly amounts for bottled water leading to it being mandatory to provide potable water out of the taps and charging reasonable prices for the bottled stuff. I can't see why airline transport would be different to that.
In fact:
NSW law - pretty clear;
Western Australia policy - note on page 2, mentions of "circumstances where patrons are prevented from bringing their own supplies" and "events of extended duration" as circumstances where a one-off event may be mandated to provide water;
Queensland policy - free/reasonably priced water now mandatory in licenced premises;
Victoria policy