Booked DD's 6th birthday party in our local church hall. I paid for a chocolate/sweet-making class for twenty kids; all parents confirmed they'd be going - great.
As people started to arrive, I noticed there were some older children arriving too, clearly siblings of the party attendees, but I was too involved with greetings and helping the chocolate workshop people set up to worry about if.
When the chocolate class started, I was busy in the kitchen getting food sorted for when the children had finished, so I didn't realise that the older children all lined up to collect chocolate-making supplies and joined in the class. The chocolate guys came up to me after, quite apologetically, and said that 25 kids had taken part, so there would be a balancing payment for the extra children. They'd told me this in advance - the package was for 20 but any extra would be £10 per child - and that was fine by me, as I didn't anticipate there would be any extra children! I reassured them that it was fine, not their fault, and I'd settle the balance, but I'm really annoyed at the parents who, firstly, didn't ask if it was okay for siblings to come, and secondly allowed them to take part in the activity. I even had to stop three of the older kids taking party bags as I only had one spare.
AIBU or is this just incredibly rude of the parents? If they'd asked in advance if siblings could come, I would have explained that the activity was chargeable per child so I was limited on numbers for that, but the siblings would be welcome to attend and have a slice of cake if the parents didn't have childcare. But to not even give me a heads-up . . . 