I don't think that alcohol should be given to kids because I have heard that their livers are not equipped to process it properly. But I agree that the USA and some other cultures make a big deal out of drinking and so kids want to do what they are not allowed. Maybe if drinking is explained to them like driving a car is, that there is a legal age because it is for adults and requires being responsible.
Parents should drink responsibly around their kids. I don't think tasting wine or beer is a bad thing. I had a sip of my dad's beer by accident (thinking it was ginger ale) and that put me off wanting to try it again, lol. So, parents could also tell their kids that they can have a 'sip' of some not-so-nice alcohol as a deterrent.
I think that the culture of drinking in Australia can be the problem too. A lot of people accept heavy or binge drinking as being normal and almost expected. This can put a lot of pressure on young drinkers to 'keep up with their friends'.