AIBU to tell SAHM not to send nanny + sibling to the party?

[discorules]

For the past 2 years at my daughters 6 year old and 7 year old birthday parties (approx 20 kids each time), one mother has rsvp'ed for her daughter and then on the day sent her nanny to stay for the whole party along with a toddler (was 2yo then 3yo). Both times I have swallowed it, handed the nanny a glass of champagne, scrambled an extra chair at the party table and party bag for the sibling, and never mentioned my "surprise" to the mother. I do think it is extremely bad manners though.
This year, I am determined that this will not happen; I'm over being reasonable, and we now have a bigger class so we have to invite 24 kids!
My thinking goes like this; the girls are now 8 and don't need a nanny at the party. I feel like this mother has used my daughter's birthday party as a convenient activity for the younger sibling for the past 2 parties. I'd never met the nanny or the sibling prior to the 6 yo party, so there's no social connection and unlikely to be one.
By way of background...
I would count the mother as an acquaintance, not a friend, and her daughter as a classmate of my daughters but not a particularly close friendship. I'm actually fine with some of the friendly mums who come along with a sibling (they flag it in advance), they help out a bit and they socialise with the other mums. I have a big problem with a SAHM (inherited big $$$ - jealous!) who sends her kids off with the nanny on Saturday afternoons (no idea what she's doing instead but it must be important) and whilst the mother is welcome to come and have a glass of wine whilst the kids are entertained, she chooses not too (I'll admit there's some social rejection "hurt" in there...I'm clearly not worth her time to hang out with!). I don't want to socialise with her nanny or cater for a surprise sibling this year. How do I say something to stop it happening a third time without seeming rude? Plus, there's always a random chance that some time in the future her daughter could become my daughters best friend, so no need to cause WWIII. AIBU? TIA!

if the other invitees are allowed siblings then this is no different.

if the other invitees are not allowed siblings then put on the invite sorry no siblings,

I think people are being really mean to the OP. I've served wine / prosecco / champagne for firsts at most of my child's parties and know loads of others that do too... people seem to be unfairly fixated on this.

Just cater for the sibling OP... if you do want to be friends with this woman, excluding her child isn't the way to go!

Why is the whole class being invited?

8year old does not need her Nanny keeping an eye on her , nor should uninvited or informed sibling turn up - it is total free loading imv, The DM has an afternoon free, Nanny has small sibling amused with no effort on her part. Chancers.

It just wouldn't occur to me to be bothered about this. It's for a few hours once a year! At my kids parties siblings have always turned up and just joined in. I honestly wouldn't notice who brought the child to the party, I just offer them a cup of tea and leave them to it. It's a kids party, just have fun!!

Snorted at the glass of champagne

TBH if I was the OP I would be annoyed at entertaining the sibling whilst the mother sits on her arse child free.

Just put "no siblings" on the invite and tell the nanny to leave and come back at pick up time. It's perfectly fine for you to pick and choose if other mums/siblings get to stay and help or not, it's your house and your party, you don't have to extend it to everyone.

It does sound as though you resent this mother for a) having money and a nanny and b) not wanting to make friends with you.
Get a grip. You know nothing about her. She might not come to birthday parties because she spends her Saturdays working at the local homeless shelter. She might have a physical or mental health issue that makes socialising difficult for her. She might simply know that you dislike her and not feel like spending an afternoon putting up with your condescension and sneering.

Fair enough not to want uninvited siblings or other adults at the party, but make that politely clear on the invitation.

Where's the father?

Champagne at a kids birthday party

Never had this at any parties I have been to or hosted

This wouldn't bother me at all.

If there were other adults staying, no problem but I wouldn't like it if I had to chat to her too especially if she wasn't my type of person.

I'd more than likely find some toys for the toddler and ask if he was hungry and cuddle him!

I thought it was quite normal to send your nanny .......

Presumably dad is 'sitting on his arse child free' too?

I'd love to have a nanny to take my kids to parties. They are so feckin tedious, champagne or not.
You just sound massively jealous of the mum.

It’s been made clear that adults stay at OPs parties, so the drop n run thing isn’t part of the issue. The issue for OP seems to be jealousy, that the child’s mum could be relaxing, and that she even has a nanny in the first place. If other people are taking siblings, perhaps she assumed her other child could tag along too. If I had a whole class party, I’d assume a few siblings would be coming, although I do agree that it’s rude not to ask if a sibling can come. Maybe the mum can sense that you’re judging her and don’t actually really like her, are jealous and a bit highly strung, and therefore she just doesn’t want to go to your party. Or she could be busy. I like socialising at my own and other kids’ parties, but if I don’t like the parents or if I find them to be insufferable snobs, then I’ll wriggle out of it where possible.

I think you’re conflating number of issues into whom attends the party. It’s okay to feel wee bit envious what’s less ok is to let that impact on how you treat this other mum.

Think about it, she’s inherited £££ as result of deaths. Cash rich, yes. But as result of bereavement. That’s not a great place to be.

I’d let the mum know the nanny can drop the kid and nanny collect later. It’s not unreasonable to not want an additional sibling at your party. You just need to tactfully tell the mum

I don't get the issue. If the mother didn't have a nanny she would have to bring sibling too so sibling not early an issue. Mother (and presumably father because why is this just a woman thing) obviously have somewhere else to be on a sat hence paying to hire a nanny. You don't know the insurance and outside of the parents life they could well have stuff on that can't be changedone. Still don't see the issue other than that you feel slighted that you are not more important than anything else in the mothers life.

Think it’s extremely rude to bring an extra uninvited sibling, unless they were a baby.

I really don’t see the issue with sending a nanny instead of the mother. But perfectly fine to suggest that parents/guardians shouldn’t need to stick around.

Just put on invite ‘sorry no siblings’
No need for explanation or elaboration.
As for the nanny stuff..sorry but you come across as a real snob! How is it any different from a grandparent bringing a child to a party? Can’t see how it matters who actually brings them, it’s the child’s party not the adults!

Thanks everyone - you had me at "pick your battles wisely"
I'll go and focus where it's important....

That’s great, OP, although we’re all invested now so please do come back to tell us what happens at the party!

YANBU, OP. We live overseas and my DC attend an international school. Many of the children have nannies. I've lost count of the number of play dates I've taken mine to and I've been met by the nanny and child, as opposed to the parent and child. When the DC got older, there was the expectation that I was happy dropping my children with an unknown nanny, when I've been expecting them to be looked after by the parent, who I actually know! It's actually pretty insulting to be told that, effectively, your company isn't good enough as the mum swans off and you're left making small talk with the nanny. I can see why you're pissed off, OP, and that's without the toddler added into the mix.

Just put on the invite: "Sorry, no nannies."

Are you desperate to be this rich woman's friend?

Nice one OP!