My mum wanted to sign up for Netflix on her iPad.

> c) bad actors will learn to trick users into making the choices they want

Bad actors have been doing this for years, abusing Apple's amazingly convenient payment APIs, like a "Heart Rate Monitor" app that prompted users to put their finger on the touch ID sensor, and then throw up an $99 IAP screen which would be immediately purchased because the user's finger was already on the touch ID https://www.wired.com/story/iphone-touch-id-scam-apps/