Should I invite extra people to allow for cancellations on the party day?

[Vacantstare]

DS 1st birthday party is in November and the venue only allows 15 children to attend. I'm sure at least one child will come down ill right before the party and cancel so not sure if I should risk it and invite an extra person now just in case that happens, as I don't want his party to be really small? But then knowing my luck everyone will be able to attend and I'll have too many people coming!

I'll be gutted if people can't make it and I never invited others to allow for this happening

First world problems, I know, but trying to be savvy....

I always did this for my dcs parties and it worked out for me. You always get one or two that flake out on the day ime.

I think that's risky. What if they all turn up?

Perhaps better to have a list of siblings / neighbours' children who wouldn't take offence at being invited at short notice

I do this to every party. In your case I’d invite 17 kids. You’ll still probably end up with a space!

What happens if everyone comes?
The entire class came to DS's first class party and we had a couple of extra friends. The venue could accommodate it, but the party room was a squeeze.
He's got a funny time of year, some years I've struggled to pull a party together so everyone accepting was a shock!

YABU

If there is a maximum capacity issue don't risk it

It would be different if the venue allowed more but you just didn't want to pay for more than 15

And if they all turn up? To me it makes them sound like an afterthought - "I'm only inviting you in case someone cancels".

I have never not had dc friend turn up for party (after accepting invite). I'd only do this is if you prepare to have a few extra.

Not an afterthought - I’d love to invite everyone we know but the venue only allows for 15 children and I’ve had to invite the whole of one friendship group because I couldn’t invite just a handful (the ones I’m not close with) because then it would get back to them and not sure what the rest would make of that!

Is it a 1st birthday party of his first party ever and at school?

If the latter, there's generally a very high attendance rate for school parties.
We invited the whole class expecting a 50% attendance. We had all but 3 accept the invite. This was a class of 30

A one year old won't notice how many people are there. If they all turn up how will you decide which one had to leave?

YABU inviting someone and then uninviting them because there’s too many kids, is a great way to fall out with a lot of people.

Invite 15 if a couple don’t show then it’s no big deal and you could offer someone to invite their siblings.