There was also a weird late-ish book (Redheads?) where the stepdaughter of some endangered policeman tracking an international gang hides out at the CS under a different name, and despite the fact she's in actual danger - the gang have specifically threatened her, and a mysterious American woman has been hanging around asking questions about red-haired CS girls - Hilda is all 'Oh no, we can't dye her hair, or keep her on school property - what would the other girls say?'
And then the wrong redheaded girl gets kidnapped, but luckily the gang realises it before they carry out their threat to get her addicted to drugs and release her, leaving her on a train with the correct ticket in her pocket. (Which I always find hilarious - they murder, rob and kidnap, but ensure their unconscious kidnap victim has the right ticket home, and when they drug her, it's in a glass of classically CS 'rich, creamy milk'!)
And - this is the weirdest bit - Hilda won't even let the kidnapped girl's mother fuss over her when she wakes up, because she's in the doghouse for having been out of bounds going to see her sick brother at the San, so the kidnap is 100% her own fault!
Someone also pulls a gun on Hilda, rather than admiring her blue eyes that had never yet needed glasses and her beautiful voice. Shock!