Ironically, those "copyists" Samsung and HTC had "reject call with text" in their Gingerbread editions of TouchWiz and Sense (I'm not sure about earlier skins since I haven't used them), even before Google added it to ICS. I'm sure both are kicking themselves that they didn't try to patent it (though I suppose patents move slowly, so maybe they have).
It's likely not patentable, similar feature has been in old Nokia phones years ago.
Many current mobile usage ideas, like e.g. location based reminders, Nokia had in design board or development internally already in early 2000s. Many ideas are common sense. At the end of the day, ideas don't matter that much, it's the execution that matters.
Oh, I totally agree on patentability, but... not patentable and not getting past the USPTO are two very, very different things.
If HTC and/or Samsung were to get their own versions of the "slide-to-unlock" nonsense past the the USPTO, that would substantially affect at least the US theater of the mobile patent wars.
