Alda Curtis, a 63-year-old counselling student from Sydney, set up a Redbubble store as a hobby, including selling a T-shirt featuring an unhappy cat cartoon. After years of running the store, a single sale of that T-shirt resulted in a US$100,000 default judgment against her for infringing on the trademark of Grumpy Cat late last year. Then Curtis noticed nearly US$600 had been taken from her PayPal account. Grumpy Cat, also known as Tardar Sauce, shot to internet fame in 2012 due to her permanently grumpy facial expressions that were caused by a permanent underbite and feline dwarfism. The American...