Hermione was suddenly, intensely grateful for being muggle-born. Even more grateful to know that her mother had enrolled her (against her will) in a CPR class at the local community center, the summer after fourth year. Hermione's parents had been particularly horrified to learn of the Triwizard Tournament, especially the event that involved sinking their daughter to the bottom of a lake. It was something that no wizard would have  ever  learned, would have  ever  thought to be important when magic exists.