My dd went to her friend's 17th birthday party. This has been planned for a while and we'd had brief chat a few days ago about whether there would be alcohol and she said yes. She's pretty sensible and has access to alcohol at home, but isn't interested and has never abused it, so I wasn't particularly concerned. Also, as it was a house party with the parents there I thought perhaps there'd be a few token beers, wine spritzers and soft drinks.
The parents had provided wine, gin, beers etc. and when this had finished they had to go out to buy more, but before doing so the mother who was clearly angry
shouted at the children they were all rude for not bringing a bottle as it was etiquette to do so.
Surely you wouldn't expect teenagers to think to take a bottle. She didn't go empty handed she took a birthday gift and card. She had two glasses of wine, so nothing excessive, but is upset for her friend who was embarrassed.