> What is a label and what is tappable!?

If only there were an easy way to find out.

I honestly think people are making too big a deal about this. The kind of people who download apps are not going to have an issue exploring the UI of new apps to figure out how they work. And it's not that hard to figure out just by looking either. Verbs, arrows, and nouns that don't label something adjacent to them should all be clickable. And if they ain't, oh man, you just wasted two seconds finding that out. Not the end of the world.