I don’t think OP meant they won’t be fobbed off as meaning they will demand to go, I think it was rather meant that they will be upset, and that the reasoning won’t stop them being upset that they’re not invited.
It’s upsetting, especially if you’re family oriented, to realise that your family don’t care if you’re there or not. And that is how it will come across to them, especially if all their cousins are invited.
Talking of entitlement, all this ‘it’s their day’ is the epitome of entitlement imho. No one owns a day. You don’t own your guests ffs. Just take a look at the bridezilla threads. And also, In my experience, a lot of time people who have child free weddings DO get stroppy if people don’t turn up. You get, ‘why can’t they leave the kids with X,y,z’ reh reh reh.
Ooh, and people who phrase child free wedding like they’re doing the parents a favour get on my nerves as well.
Like I need your permission to have a child free night 🙄
But that’s all irrelevant, as this isn’t even a child free wedding, just one the OPs kids are not invited to.