This is wrong. How the hell did we learn "pinch to zoom" on the iPhone/iPad was a thing? We were shown! Lots and lots of demos to re-enforce the action and get users accustom to a thing is fine if that experience doesn't frustrate the user and they can get up to speed using the app quickly. If you are choosing neat new ways of communicating and changing the way the user interacts with the app for the sake of being ne…
I'm not so sure about that. My grandmother, who certainly had not seen an iPad or iPhone in action before (she's 85, doesn't speak English and doesn't watch TV), figured it out within one minute of using my iPad for the first time yesterday.
If you think about the pinching movement, the distance between your thumb and index finger correlates to the size of the object. Increase that distance and the object grows in size (i.e. you zoom in). And vice versa. This is what I'd like to call "hyper-intuitive" and is the kind of thing people can figure out without being trained on it.