To say no when asked if sibling can come to party?

Sorry, what?

Parents who have childcare options have childcare options. But not everyone does have childcare options, obviously.

"I'm afraid not - others have asked and due to space I've had to give a blanket NO to be fair to everyone."

Other parents have presumably managed to sort out child care for a couple of hours.

If this sudenly happens (it won't) then you can just say 'sorry, we've already got a few extra siblings and I don't think i can squeeze any more in.'

It's not a case of being respectable. Maybe they literally don't have anyone else to have the 5 year old.
Many people are fine with siblings coming along so I don't think it's rude to ask as they could miss out unnecessarily.

Also think YAB a bit U. Unexpected siblings come with the territory of nursery parties. DD’s pre-school class is age 3 and up, so her 4th birthday party had a range of 3 year olds to almost-5 year olds, and a smattering of 2 year old siblings. There was a bouncy castle, none of the giant almost-5’s piled on and ruined it for the just-turned 3’s.

Having been through 3 years of infant school and I'd estimate approximately 60 parties I'd honestly say you need to get used to this - it is absolutely the tip of the iceberg.

People will rsvp the morning of the party, not rsvp and turn up anyway, turn up with unexpected siblings, rsvp but then not turn up, not tell you in advance about allergies/dietary requirements, drop and run and turn up late to collect.

I agree with this. In our circles people tend to say yes to siblings unless it's a paid activity type thing. I would feel bad for saying no to my DC's friend's sibling, and I've always let people join in even if space has been a bit tight. People always end up dropping out at the last minute anyway, and one 5-year old will probably merely pick at some cocktail sausages and have a bounce in the bouncy castle. 😂 Maybe your DC will make friends them and would be all proud of having an older friend. 🥹

Surely if the parents are staying (which at 3 they certainly should be) it’s not really a big deal?
We often had 25+ kids for parties at that age, but parent’s stayed.

I agree with this. For all my kids' birthdays we've always had a few extra siblings turn up and I don't mind. I'd appreciate it as well if I was stuck for childcare. In a few years it won't be an issue as parties become drop and runs.

If the parents are expected to leave DC, I'd say yes, you refuse, but if you're expecting parents to stay, I think you have to say OK for the sibling, and realistically, it makes no difference to you, as his mother will be responsible for him.

I think it's a bit harsh to say no. I couldn't imagine anyone in real life saying no to this. I get the reasons you would but I think there was nothing wrong with her asking.

Yabu, it is one 5 year old child. It is hardly going to "change the dynamics" of a bouncy castle party in the back garden!

I don't think 1 more kid is going to make a huge difference to the chaos, I would say yes.

Bingo! I joked about this upthread

It may well only be one extra DC but if more requested bringing siblings could/would you want to cater for them also?

No if you know the child and she's one of those bossy little madams who will start organising the younger children.

Yes, if she does as you tell her without getting in a strop.

It becomes unreasonable when you have to pay per head for a specific activity and it costs you. When you need parents to attend then it is likely people will need to bring siblings. Inconvenient perhaps but that's the reality. It is not going to be every child bringing a sibling and she wasn't late to rsvp or cheeky to ask. In their shoes would you want your dc to miss out on so many parties? What about in school when it's their friend's party?

I’m usually one for setting clear boundaries and being comfortable about saying no, but I’m two children and many parties deep now and it’s definitely expected and accepted amongst most parents that a sibling here or there will come (though most respect obvious boundaries where paid events are being hosted). I don’t think it’s a huge deal for one sibling to join.

In what world is it petty and selfish to host a party for ten 3-year olds?

I was at birthday parties in the 80s and my sister in the 90s - was all drop offs as far as I can remember. Only parties my mum was at with me (single parent too) was my own obviously or my cousins’. Friends parties was dropped off and picked up from young

Similarly I was never dragged along to a party my sister was invited too

No is a complete sentence.

Out of interest, how many children do you have? Speaking as a parent of two fairly close in age, it is difficult when invited to things that you need to stay at, to make alternative arrangements for the sibling when you are the primary carer. That said, this is a weekend party so unless she is a single parent, there is presumably a partner who can watch the 5 year old? If it’s the case and she wants to bring both to give him the morning off, that’s a bit cheeky. If she has no partner and therefore no childcare, I think it would be fair to include the 5 year old.

My children were born in the 80s and parents always stayed at parties for pre school children. And if they had siblings the assumption was the siblings would also attend if there was no one else to care for them. It was never an issue.