If it's ok, we'll all come

[Lights22]

As an autistic mum pretending to be a normal mum around all the other mums pretending to be normal mums, I need your help with this please.

Invitations have gone out for DD's birthday party at soft play. Messages of delight, excitement and acceptance all duly come in. Then this one: "she'd love to come. If it's ok, we'll all come. Me, DH and little sister (3)".

So, is the mum asking for an extra party ticket?? Free entry to soft play + food + party bag, or is she just saying younger sister will just be in tow?

And if it's the extra ticket, how do I skillfully say of course come but pay your own way?

Remember, I'm trying to look normal and nice and kind and not overthinky or stingey. Just setting a boundary like a normal person!

Just to say, when our DD was invited to a soft play party, we all went too but paid our own entry for younger DD, got our own food and kept her away from the party. So this could be what they're thinking too? But if so, why ask?!

sometimes families don’t get much time together - maybe they were planning a soft play or little sis is feeling left out, or parents want to see kids at the weekend, or they have family to visit near by…. I cannot imagine the soft play are going to invoice you/reject another party guest. It’s a child’s party. Dont worry too much. Suspect other parents may bring other kids too and just do their own thing.

Tough one OP. I wish would make themselves clear in their intentions!

You see i dont find this cheeky at all. The siblings would always come in our circle and sit as a group elsewhere. Often at weekends one parent might be away/ working, single parent, one car
If its a public venue it's not cheeky at all.
A lot of parents would check with me, some wouldn't bother as it was open to public.
I'd just confirm in my reply that they can pay at door I.e we didn't have private hire

Well the child needs paying for, either by the birthday host or the child's parent. I haven't known an actual venue let children in for free just because it's a party (usually there is a higher charge if it's a party as they charge per head including entry, good and party bag plus covering the cost of a party room). At the soft play places near us they ask you to sign in and write down the names of the children when you arrive, if it's part of a party they have a list of names separately for that - imagine being the host and then being presented with the list and told that 5 more have been added and then asked to pay for them because people brought siblings and decided to say they were all there for the party. I would be really upset that people did that.
This is why it needs to be made clear that if it's a venue that is open to the public it's fine for a sibling to come along (as the OP can't control who is there and who isn't) and to make it clear they will need to pay for their entry and food.

This

The problem is, accommodating one sibling is no problem. But you could end up accommodating 5 or 10. We had a smaller party for my DC this year (under 20). It was £20 a head. I added in a couple of siblings as favours to friends who’ve done the same for me but if I’d added in every sibling who came (where parents reasonably expected to pay for their own entry), it would have been an extra £100 on top of the party. That’s quite a lot!

The problem is, accommodating one sibling is no problem. But you could end up accommodating 5 or 10.

Plus, if the party is for, say, 6yos, they won't want much younger children trying to join in their play.

And for the invited guest whose family tags along, they don't get the opportunity to socialise independently.