Looks like the ATO is going to be busy in Australia. Even an Amazon one in there that shipped without GST.
Strict rules of sovereignty should be maintained. I'd like to think most foreign courts would tell the ATO where to go if they tried to persecute a legal entity operating outside of Australia, but I am reminded of this example...
New Zealand should take the lead here and specifically legislate against foreign nations attempting to impose obligations on us. That's not what will happen however. Eventually there will be reciprocal agreements, and we'll all be forced to pay taxes everywhere. The practical aspect of such things may come later, but until then, it'll be a horrible burden on businesses. It's certainly caused me to re-evaluate my plans.
Its a local tax, been around for ages. Or, when online sales really ramp up, GST will drop, so lets whip up Income Tax for the difference. OR continue with GST as has been the case forever. Most of our purchases are imported, no matter how or where you buy from.