Which I could totally understand if it wasn't complimentary
Regardless, I'm yet to visit the states on my own (last did so as a child) so will inevitably learn by then. But it does seem hard in an increasingly plastic world to tip... I never carry cash in Australia for instance.
And I thought America was the most plastic place in the world
Complimentary supply, not service.
Also, if you're an Aussie and you tip, you get remembered. I know for an example that notzac and I are still known in certain AA AC's due to the fact we are "Aussies who Tip".
Australians are known for not tipping. Either they think it's wrong, don't understand why it's expected, or genuinely have no idea how the whole tipping culture works.
If you're an Aussie who Tips, you're going to be remembered, and chances are, you'll get better service than most.
I'm all for paying lower prices for booze anywhere in the US and leaving a few singles for the staff. They're more likely to be more generous with the pours (what's 30mL? You meant 90 didn't you sir?) if you tip them as notzac suggested, 100% of the drink price on your first purchase, then a single per drink thereafter. Obviously that doesn't hold true for bottled beverages.
It really is a case of when-in-Rome.
I will tip in AU or most other places in the world for excellent service, but in the US, i'll tip to get the service, and enjoy cheaper prices. Chances are, even with tip, you're going to be paying less than what the equivalent food/beverage would be here (and you're not required to tip in Burger King or the like, it's only non-fast food and bars).