I generally agree with 'Everyone else not in the target group must pay this tax as well for no particular reason' being stupid in other areas, but I don't think it applies so much here. Young people drink these drinks because they don't like wine or beer. So, they are drinking PURELY to get drunk. Otherwise they can just drink the soft drinks on their own and get the same taste with no alcohol.

Beer for example is an aquired taste, more likely aquired by people mature enough to understand the pros and cons of binge drinking.

When you sweeten alcohol in mass produced cheap lolly water drinks, you're really marketing to children. Make these drinks really expensive for the kids to buy, because that will reduce consumption, while the adults can drink propper drinks like wine and beer.

Anyway, it's a lot harder for the teenie boppers to scull down beer and wine at the same rate as these acoholic sodas. As I said, I don't think most of the non-target group are affected in this case.

Taxation has already created a black-market for cigarettes/tobacco.
A very easy plant to grow in your backyard.

Why not distil or home brew your own alcohol?

You could probably make some fuel for the car while you were at it! :)

See here for a discussion of the law on this:-
http://forums.permaculture.org.au/viewtopic.php?f=1&t=5500&hilit=petrol+excise