Oooh, I like your last paragraph, Mel! Very true.
I am one who does not believe that allowing a sip upon request is harmful, given the right convergence of circumstances. My mum often drinks too much. My dad doesn't drink much, even at parties...and he's Irish. DP's family has been touched by drink - my FIL was an alcoholic (a 'benign' one, IYKWIM) and my MIL drinks beer not even in moderation, just from time to time, and not much. The last time I was sick from drink was the night before my sister's wedding 3 years ago. I have always been aware of alcohol, but not as a taboo. I had sips as a child and I understood it's nature in my family as something that accompanies a meal, or to share with friends. I didn't even start buying it when I turned 18, because I had enough with having half a glass maybe once a week at home, usually a lot less often than that. My sister got started with beer with her friends when she was still at school. Same family, different directions. We went through our 'phases' and now neither of us drinks a lot again.
I am not going to have a blanket ban on alcohol for DS in my house. DS will see that his grandma can't hold her drink. He'll see that DP sometimes has too much and whilst he is funny and goofy when drunk, his uncle is just unpleasant. He will see that his grandad (my dad, FIL passed away) gets so sleepy that he becomes useless. As he's still breastfeeding, he will see mummy have a small amount of wine on a weekend, or out with friends to dinner, and he will see me retain my dignity. So, he will not see just one outcome from alcohol. He will see that it is something that must be treated with respect.
I think it's awesome that the OP was even consulted about permission to serve her daughter alcohol. To me that reflects well on that parent. It also instills in the kids (as much as they are resenting it for now) that alcohol IS to be respected, and not treated as a right.
Yes, sadly, our Australian culture does not impart a respect for alcohol. It's a given at just about all occasions. That's sad. It is also, somehow, a given that one must become obliterated on alcohol to get the full effect. Unlike other cultures, where the effects of overconsumption are known, we expect alcohol to be excessively drunk at parties and functions. It's a wonder anyone drinks fine wine or good beer just for the taste or for a very mild relaxation effect. People accuse you of being straight if you stop drinking once you can feel an effect. I'd rather be the straight one than the one who feels queasy the next day!
By the same token, I very much respect the stance that other families take with alcohol. If you've gauged the situation and consider that no alcohol is to be consumed till children are of age, then I'm a nobody to question your particular situation. You have your own family histories, local custom and expectations, cultural dynamics to consider.
I think it's great that this thread has caused a few of us to assess our own situations!