Instead of the near undetectable counterfeit eggs, some counterfeit products are easier to determine. See the video, where counterfeiters made some mistakes, here.
The buyer of the fake boots was lured into buying the booths because it said: "100 percent Australian made". And the label said "Made in New Zealand" (see picture). That information was wrong, because as the eBay Guide 'How to tell fake UGG booths' tells you real UGG Australia booths are made in China too.
At the UGG Australia site you can fill in a URL at a search bar to see whether UGG Australia can guarantee that the products sold from that place are genuine, see here. That does not solve the problem for parallel import or discounts via other sites.