not coming to a child's birthday party

[Tri Girl]

That's sad. I teach, and my rule is the same as hers: you can't pass out invitations unless everyone is invited (well- I also say that they can just invite the girls or boys, but it has to be every girl or every boy). I'd love to not have invitations passed out at school altogether, but that's not likely going to change. Other than that, I stay out of it. Parties are an after school event, and I've got too many things to do to monitor another thing that's far beyond my control.
In a way, the parents are to blame for this: too late notice it seems. Even if it were a child with more friends, 3 days notice isn't much for the weekend. If they'd sent it home earlier, people might have had a chance to attend. I don't know. Touchy subject here. Although on 3 days notice, 6 attendees isn't too bad. I'm glad your son went.