EDIT: JaneSA, I hadn't read your post just above when I wrote this but you might have been the person who posted about rural workers a day or two ago?
There was a post a day or so ago that said Karlie must have had a bank account to get paid for casual work due to ATO crackdown on tax avoidance by rural workers. I don't believe that is correct. Many waiters, shop assistants, etc are paid cash in hand.
Similarly you are not required to get tax file numbers or pay into a bank account for people who work for you as casual contractors, such as occasional handyman services. GST is only payable for services, and a tax invoice required, when a service provider earns a certain amount per year for his or her services, I think $75,000.
An employer could face fines for employing someone without getting them to sign necessary ATO forms but the ATO does not have endless resources to go around checking Australia wide other than on a random selection basis or as a result of a tip.
Gino and Mark Stocco, the father and son who are "on the run" in NSW at present, apparently lived by working in rural areas and are said to have lived "off the grid" for 8 years. This Daily Telegraph story describes living off the grid as living with "no phones, licences, bank accounts or friends".
http://www.smh.com.au/nsw/stank-lik...for-gino-and-mark-stocco-20151018-gkc2i2.html