My dd is 12 and at her school the convention is that things like party invitations are still issued by the parents (ie the parent sends a text or email to the other parents). It’s dd’s birthday soon and I have invited a few girls to an activity. Some people replied straight away but some have not even though I sent a polite and “breezy” follow up after two days. I suspect the relevant girls just don’t want to come but I think it’s a bit rude not to reply... Why do people do that?