Check her grades first
When I was in grade 2 and got chickenpox, I took an early summer vacation (started february) coz my grades allowed it. so being a nerd aint all that bad after all.

If she misses the exam and has to repeat, next year's tuition wil still be more than the money theyre gonna save on cheaper airline tickets. So, if her grades won't allow her to be exempted from the exam, tell her mom to bite the bullet and fork over the 20K. The cost of repeating the same grade/summer school would prolly exceed the savings with the ticket, plus there's the stigma pa of being a "repeater". We know how cruel kids can be sometimes.