[youtube]http://www.youtube.com/watch?v=gGyfnzI7ZaAFor the past four months, shoppers in South Australia have been encouraged to bring their own bags to grocery stores. As of today, the state has officially banned single-use plastic shopping bags. We've covered similar measures in U.S. cities and other countries before, and as with all previous examples, we'd like to offer a tip of the hat.There are a few exceptions to the prohibition-such as the small plastic bags in fruit sections of supermarkets, the heavy-weight plastic bags at some clothing retailers, and some compostable bio-plastic bags (not unlike those discussed in today's Look piece)-but this should result in a dramatic waste reduction.The above PSA would seem to have helped in prepping people for the shift, but I'm guessing that only now-that is, now that the bags have been phased out (and now that stores face the threat of $15,000 fines for using them)-will the real behavioral transformation take place. My only criticism is that the same thing isn't happening soon enough over here. Then again, 2010 is right around the corner.