(This is quite a long one with several questions. Answers to any number of these questions are welcome but please provide a source/reference.)
I am in Australia on a 417 working holiday visa. I have recently got a job as a bartender. During my trial shift, the owner of the business stated to me "we pay $20 an hour, and don't take tax", which suprised me but I don't know the tax system in Australia so I kept quiet. He did not take my tax file number (or even my surname amazingly), and pays cash in hand.
I am returning home to go to university in September, although I know I will return after graduating, possibly with intentions to get sponsored and become a permanent resident. I would like to know if, for whatever reason, this failure in paying tax is my fault or my employers. Will this affect my chances of getting my visa renewed/getting a new visa? Upon leaving, will any authority (immigration/ATO) ask about my employment during my year in Australia?
After doing a bit of research, I have learned that for taxation purposes I will be classed as a foreign resident, and therefore get taxed something like 30c for every dollar I earn. I am reluctant to find a new job since, if I earn $20ph again, I will probably pay tax which will reduce my wages to about $13ph rather than the $17 I am currently on (I realise I will be able to claim this back but I am aware that this can be a time-consuming process, and I probably won't get 100% of my money back).