Ask HN: Why does Apple want me to expose my iPhone password to repair my screen?

I went to the Apple "Genius Bar" today to get my iphone screen repaired (it shows only a white screen). They told me I need to disable the "find my iphone feature" before they can start the repair. This requires me to confirm it on the phone itself - which does not work due to the broken screen. So the apple staff handed me a "Showcase iPhone" of the apple store which had a "apple support" app on which I need to enter the password of my phone. I have no idea what this apple support app is doing or if it is legitimate at all (ass this is a show phone where many people have access to). I ended up leaving without repairing the phone and now consider to go to an unofficial screen repair shop. From a security point of view that does not look like a very good approach. Any thought on this?

There is a discussion on Hacker News, but feel free to comment here as well.