Patents aren't intended to protect an existence proof. They're intended to protect the underlying methods. If, after seeing a swipe-to-unlock gesture on an iPhone for instance, someone of ordinary skill can implement it without referring to the teachings of the patent, then the patent is bullshit.
(Of course, that's not the way it works, but it's the way it should work. Remember that patents exist to give inventors an alternative to keeping trade secrets. Something that would make a laughable trade secret should also constitute a frivolous patent claim.)