Just got back from byron, having discovered that yes you can be arrested for underage drinking in public...even in byron.
I think i just got some neo-fascist cop on a massive power trip, because his partner was really calm about the whole thing while this guy stood and swore at me quite a while.
Tips for the future:
1) Don't try and run.
I nearly did, in a severly drunken state, and it would have only meant a resisting arrest charge on top of the underage drinking charge. A friend up in surfers tried to bolt after the police up there fined him for urinating in public. He is the GPS 400m champion, so all would have been fine had the riot police not tackled him at the end of the block.
2) Don't tell them you're 18. I did initially, and then claimed I didn't have my wallet, but they have the power to search you so i pretty quickly ate my words and claimed stupidity.
3) Don't give them a fake id, scratchie or look-alike. Underage drinking is one thing, fraud is another. The police are not stupid security guards or bouncers, they actually had to go to college and pass exams.
Just be totally honest, but don't try and suck up either. Usually they will just empty your drinks, however if you're mildly retarded like I and stuff around first, they'll write down your name and issue you an official warning. If you're a total moron and really piss them off, then yes they will arrest and you, charge you and keep you overnight.
Most of this will seem like the actions of a total dumbass, but when you are quite drunk, cocky and with a group of friends, quite often you are a total dumbass. All of these things did cross my mind, I did start to try and run, I did reach for my fake id, and i did tell them i was 18 - moronic in hindsight, but hey. And remember, this happened to me in byron where there are about 4 police officers, in comparison to surfers where there are more cops than schoolies (not counting toolies, who today are the majority).
And don't think that quietly drinking in the corner exempts you. We had to be the quietest people on main beach, in comparison to the lads trying to break the public lights, and they still went for us.
Get sloshed at home. Or better yet, be 18.