To think 'can I let you know nearer the time?' is rude.

If you'd read the thread you'll see there are lots of reasons people won't be able to commit yet that don't involve waiting for a better offer

Wow. You really have limited imagination if you think it's merely that people are looking for the best social offer.

Staff rotas may not be out. They may not know until they know if they are scheduled to work or not.

They may be waiting to find out if other members of their family are free.

There might be 100 reasons someone can't confirm yet that have nothing to do with whether they feel like blessing you with their presence. Are you always this paranoid?

Isn't this why you have an RSVP date?

This is one of those things where context is everything. Personally, if I had to do that I would explain why, "Can I let you know nearer the time - I'm still waiting to hear exactly when my PIL are arriving but it's supposed to be that weekend and that might impact whether or not we can attend".

But I also would NOT assume they realise that if they can't come you'll work down a list. A lot of activities have a minimum number, but the final number can be confirmed just a few days before. So they may well assume that their yes or no is not a big deal.

you need to just explain that you need firmed up numbers as you can't have a late cancellation.

Perhaps they think you can wait a bit. If you can't then let them know.
To and your thread, no, it's not rude. It's just factual. As others have said it ca be for a while host of things. Not just your suggested scenario of 'something better may come up'.

Family getting back to them about plans they've been trying to organise. Shift rota not out yet. Other plans that came before your invitation that are similarly in limbo waiting for others to confirm.

Yes but it depends on their individual circumstances. For example I needed to know when BIL and family are visiting from overseas as they are staying with us. It was one weekend or another. Both had to stay open at my end until they confirmed. Now that I know, I have a very clear picture of my calendar so I would be a straight up yes or no. If a friend does this consistently I would be annoyed but not in the scenario you describe.

Or be honest when asked and say I don't know yet. If that doesn't suit the inviter, then they can also respond honestly and say so. But I don't think there's anything wrong with being truthful in the first place.

I think they should say why rather than just say that as it could be waiting for a better offer or for a genuine reason.

When DD was waiting for her latest operation we knew we'd get a three week notice of it because of things that needed done before it. So there was a couple of things that we had to say "sorry, but we can't confirm anything more than 3 weeks out atm as we may be in London for DDs operation"

Well, if you accept the party invitation they won’t be playing because you’ll have accepted the party invitation?
Or if you’d rather keep yourselves available in case theyre asked to play when the party is on, then do so, by declining the invitation.

It depends if they don’t know if they’re working/ have a lift/ waiting for a hospital appointment etc. it’s more likely to be something like this than ‘we’re waiting to see if they get asked to something else’

No, it's not rude, they've asked, ignoring the invitation would have been rude, or accepting and not turning up. You can tell them you really need to know by x date and that's that.

You’ll get a lot of apologists for it but yes, it’s rude. It’s a polite way of saying “Yes, if we don’t get a better offer”.

There are a small number of situations when it could be fine - for example, if you know a family member is visiting at some point during that period don’t know exactly when yet. However, in those circa I would just say that - Granny coming from Australia around that time, not sure when but may be able to if doesn’t land on that weekend. Will check and come back to you ASAP [or] will have to decline on this occasion.

I don't think it's rude exactly, but certainly inconvenient for you. There could be 101 reasons why, not just "keeping options open in case something better comes along".

For example, if there's illness or a potential terminal situation in the family, heaven forbid, the received wisdom is to keep things normal for kids, but giving a definite yes at this stage might lead to a later cancellation/disappointment.

From your end the "needing numbers" etc is a good way of clearing it up.

I've had to do alot of "can I confirm closer to the time" for things because 9 times out of 10, thanks to frail elderly parents, laying down a solid plan too far in advance almost guarantees a sodding spanner in the works. That said, I do try to confirm or not in enough time not to be a complete twat.

I can't predict that far ahead because of kids sports activities. There may be nothing currently scheduled, but between cup matches, knockout rounds, end of year events, etc, there's no way of knowing whether they will be playing that far ahead. And that's only football and one age group.

This.

I agree OP but I also realise that around Xmas there are other things going on. But, people can’t expect you to hold a party place for them.

Just make that clear to people instead of not doing so then complaining they're rude.

This is why I voted YABU.
My DC has a number of friends in one parent families, or large families where parents work shifts. Most of those only get their shift pattern 2 weeks ahead, some of them just one. They then need to arrange relevant childcare/transport to clubs and activities.
I always explained what notice the venue needed and let them make a judgement call based on that.
It's a bit annoying but it can't be helped. Not everyone can work 9-5.

I think you should explain why and accept that you might have to miss out.

I recently replied to an invite with 'she's committed to a netball match that day and we don't yet have the time - when do you need to know by - understand that if you need a yes/no answer now, then it'll have to be a no' - the parent was happy to wait.

It's absolutely fine, assuming that you can give a good reason.

'i really hope (child's name) can come, but I'm waiting on my shifts for that month, and if I'm working her grandma will be doing childcare and won't be able to get her there. Is it okay if I let you know in a week, when the shifts come out?'

I'd have no problem with that at all.

Phrased as a question it is not rude. If you need to know immediately then you say so, if you can give them a week or two then you do that. It's a perfectly reasonable question.

Phrased as a statement ("I'll let you know nearer the time") it is rude.

I’d be ok with it if someone said ‘Can I let you know when the rota comes out next Wednesday’. I wouldn’t wait for an indefinite amount of time because you have to pay for places and need to know who’s coming.

Somebody with a work rota or a possible family visit conflict would have said though, surely. Then you could have found out when they could make a decision and decide whether you could wait that long. Expecting you to wait around with no idea about when they will make up their minds is rude.

I think its rude. If you are unsure then it's a no.

I would say you need to confirm numbers so will count her out and invite someone else. Then she night learn that it's rude and not everyone is hanging around for her to decide if they can grace you with their presence.

Oh, ok. Still in term time is fair enough.

Just tell anyone who can’t confirm that you need definite numbers now.