The first time somebody handed me an unlocked iPhone asking me to send a SMS (she was driving) I wasn't able to do it. I had to ask her where to touch. She was really surprised. I had a few years of experience on Android and 10+ with feature phones.

On the other side, I asked another friend of mine to take a picture with my Android phone a couple of weeks ago and she (an iPhone user) wasn't able to find the camera app. I had to open it for her. It was on the home screen, maybe it's different on the iPhone.

On iPhone you can swipe left on the Lock Screen, or press the icon on the Lock Screen, or you can pick it from a menu you pull down from the top of the screen, or find the app via icon, search, full app list. Maybe other ways I don’t use or know.

I would assume that it’s similar on android, access the camera from lock screen or app. I’d probably try the iPhone style swipe the lock screen if I didn’t see a shutter or camera looking icon, otherwise I’d use search (if I could find that) to find the app.

Maybe that's what happened. I removed everything from the lock screen and she could have inadvertently locked the screen.

Yes but on the flip side I don't give two shits about discoverability, I already know how to use my phone. Snapchat is actively terrible for discoverability but it's really efficient once you know.

The best design for someone who is unfamiliar and the best design for the user that already knows how it works are always at odds with one another. Do you balance the game for new players or for diamond league?

Exactly this. Design is always a compromise between discoverability and post-discovery efficiency. Programming languages are the extreme case of the latter; literally everything requires a reference, but once you’ve got the reference memorized you’re invincible.

If they can’t read “swipe up to open” then they’re going to have a rough time in life in general

But that text is a lie! You can't swipe up to open. You have to swipe up from the bottom to open. So not just a general upwards swipe.

Precisely. And the text isn't even guaranteed to be there (I don't use iOS).

Seconded. Wasn't able to unlock one the last time I touched an iPhone. And I even owned one - iPhone 5. Some people I talk to share similar experience.

Yeah from someone who supports users sometimes they have no idea how to use their iPhones.

I had to Google how to turn on an iMac.