If somebody gives me good service, I'll tip them. Housekeeping staff, waiter, driver, whoever.
If somebody doesn't give me good service, I won't.
In Australia it is not expected the same way as it is in the USA, but I'll still do it if I feel like it. The amount of money they might get paid doesn't factor into my decision at all. I make my decision based solely on whether I think their service was good.