Would You Pay For Missing A Party?

In England, a five-year-old named Alex missed a friend's birthday party. You know, shit happens when you're that age. Alex's parents were shocked when he came home from school with an invoice for $24.12 in his backpack from the parents who threw the birthday for missing the event. CNBC reports that the party-throwing mother is so incensed that she is threatening to take Alex's parents to small claims court if they don't pay up, and maintains that since Alex RSVP'ed yes, his parents should pay. The teacher at the school who was implicit in delivering the invoice to Alex's backback from the angry mother has been reprimanded by the school. What is your take on the situation?