Five-Year-Old Boy Gets Bill for Missing Birthday Party

We've all missed parties we planned to go to. But this little boy might be paying for it.

A couple of parents in England are going head-to-head over this very faux pas; after agreeing that their son would go to his classmate's party, one set of parents decided to send him to his grandparents' house instead.

Unfortunately, they didn't let the mother of the birthday boy know about this, and she was stuck with paying for the attendance of someone who never showed up.

Pretty annoying and rude situation, right?

It's just getting good:

[O]n January 15 she looked in Alex’s school bag and found a brown envelope. It was an invoice for £15.95 for a child’s party no show fee.

 

Yep. The mom brought in an invoice. For a missed party.

She's now threatening to take the family to court if they don't pay the fee.

So who's the problem in this situation, the parents who skipped a party they agreed to attend without notice? Or the mother for sending the invoice? I'm going with option C.) both sets of parents, for allowing it to get to the point where they've dragged children into a petty quarrel, but that's just me.