You only need to see once, the "slide left to right to unlock" feature to be able to reproduce it in your platform without having to look at any piece of code. The idea is not obvious, but the implementation very much is and that's what patent are supposed to protect, implementations. (I'm picking on Apple there, but that's just an example on top of my head, software patent are all like that, except exceptional algorithms that are back by math behind and are therefore ironically non patentable )

It is like the light bulb patent. If just seeing a light bulb would have allowed any electrical engineer to make one over the we in his garage, I don't think it would have been patentable.