bags, what a disgraceful way for the mother of the birthday sleepover child to send to other parents.
When ours were the age of mini bags, I was seen as a harridan for refusing to agree that mine could drink alcohol at the homes of their pals but worse, for absolutely refusing to allow my 15 year old to have "alcopops" (all the go 15 years ago) at her 15th.
I find it hard to believe that any responsible parent would put other parents in the position of normalising under age drinking. If they were going out for a meal I may just about agree to one alcoholic drink but the notion of a group of 15 year olds, being given the go ahead to drink alcohol at a sleep over beggars belief.
We took our 15 year old and a group of her friends to the cinema at our local shopping mal (it was very trendy years ago). We delivered the 6 safely, bought the tickets and abandoned them at the door, planning to collect 3 hours later. An hour later, another friend who'd luckily been picking up her own daughters phone me. She'd found one of our 6 unconscious outside the cinema. She and another girl had slipped out of the cinema, persuaded a man to buy them a bottle of vodka, which she'd proceeded to knock back. She was in hospital overnight and I had the job of phoning her parents to tell them how ill she was. Luckily, she made a full recovery and the other parents didn't blame us for their daughter's behaviour.
Cautionary tale I think. Best of luck with your conundrum