A good question

Somehow I don't see the benefits of such a law outweighing the costs. It just looks like more Wellington wowserism to me. I have to agree with Brad Taylor when he writes,

As it happens, I don’t think government should be concerned with reducing the social costs of alcohol: I think they are much smaller than the social costs of any policy intervention I can imagine. Even if we accept the need to Do Something, however, Palmer’s proposal worries me more than other (perhaps less efficient) means of alcohol control.

Since being drunk is arbitrary, the proposal would give police more arbitrary power. As someone who takes the rule of law seriously, this worries me more than the (very high) cost of excise taxes on innocent drinkers. Unless you think being drunk is itself wrong, in which case I don’t much value your opinion, this gives cops another legal weapon to brandish against innocent people they don’t quite like the look of.