I just received a call from a NSW police officer who asked me where I lived. I asked why and she said they were knocking on my door and there was no answer. I asked the address and it was where I lived about 4 years ago. I asked where she got that address and she said it would have been from the immigration card I filled out on entry. I said I live in VIC and put down the correct address. She was nice and was just doing her job so I didn't give her a hard time, but it looks like they are checking up on people who have come back from overseas.