You’d have to be pretty seriously ill not to know within 24 hours’ notice in time to inform the court. They can hold court with you on the phone or Skype so it depends what you mean by “genuine illness”. After all, how ill would you need to be to be incapable of looking after your children – which is what the hearings are about ultimately. From personal experience, if I have food poisoning, or flu (as opposed to a bad cold), or a broken limb, etc, then nappies still need changing, dinners need to be on the table, schools need to be attended. Same goes when the money has run out or the washing machine/car has broken down. That’s real life.