Erm, as a waitress in Australia, I don't think tipping is rude. I love getting tips- I consider it extra, unexpected money so can use it for things that I want but don't need. Going to see a movie, eating out: stuff that as a uni student, doesn't really make it into my budget.
It's also worth addressing the common misconception that waiters are paid a lot in Aus. The place I work at now pays minimum wage: $18 an hour. I consider that pretty good money. However I have worked at places and been paid, $15 and even $12/hour (full wage, as an over 21 yr old). Don't get me wrong, this is illegal, but it happens at a lot of places, especially in the city. When I complained about the illegal wage in the $12 place there were suddenly no more shifts available. When I called FWA they couldn't help me because the restaurant wasn't giving payslips, and I had no proof.
I'm not saying that you should tip if the service is poor, and tbh, often a customer that comes up to me and thanks me is as lovely as a tip... But an extra $10-$20 over the course of an 8 hour shift can make a big difference to a pay packet at the end of the week.