If you were a politician and I told you that you had to raise $500 million through a new or raised tax, who would you impose that tax upon?
People that don't vote, of course.
Governments at all levels have decided that "teenage binge drinking" is the new "global warming". It's difficult to read a newspaper or magazine without coming across some shock story about drunken teenagers.
The easy thing to do is to simply impose a tax or fine upon something you don't like. But it doesn't actually solve the underlying problem. (But it does raise your taxation revenue!)
It has to be asked, where are under-age drinkers getting their booze? Half the time, it's the parents providing the liquor. The rest is an older sibling buying it, usually funded by pocket money or a part time job.
The target demographic typically lives at home, with their parents. They have no expenses, and therefore, a high disposable income (assuming a part-time job). For the half where it's the parents buying the booze, an additional cost won't even be noticed. For the rest, the additional dollar will make little difference.
When will governments start blaming the parents? Kids playing R-rated video games and drinking should not be the government's responsibility to rectify. It's the parents' responsibility. Governments need to analyse the underlying causes for an issue, instead of the typical knee-jerk reaction the media has come to love.