Miss Manners: Party crashers at my 8-year-old’s birthday

Dear Miss Manners: I had a day enactment for my 8-year-old lad astatine a trampoline park. The enactment bundle requires an nonstop headcount, and charges a alternatively steep interest per child.

Along with my son’s friends, we invited immoderate of their siblings, whom we are adjacent with. A genitor I’d ne'er met showed up with her son, who’d been invited, and her mediate school-aged daughter, who was uninvited and chartless to us. She announced that her girl would beryllium “jumping too,” that she had asked the unit and “they person capable wristbands,” and aft all, “I drove here.”