Re: Car Sharing
Generally your insurance will be void in many countries if you get a "bit more for effort."
I don't know about Australia, but that is definitely the situation in Germany, where Uber is banned, but still operating, AFAIK. If you are driving from A to B anyway, you can take a passenger with you and drop them anywhere on the route and you can ask them to cover fuel costs (time, effort, wear and tear not, as these would have happened anyway, because you were making that journey with or without passenger).
If you charge more than the fuel costs, then that is commercial and you need commercial insurance, to qualify for commercial insurance, you need to show your taxi licence.