Ugh that sucks, Pap!  I've imagined now how I might react if they came to my door, would I engage them in conversation?  Would I tell them I am one of them?  Would I tell them I'm an apostate?  Would I ask the unsuspecting all my deep-seated questions, knowing they couldn't answer them, but just to watch them squirm?  
(In all actuality, I would probably just hide in my bedroom like a pansy until they left.)  Shame2

But to have them send you a letter!  That almost feels like even more of an invasion!!  Like, it's in your hands! In your house!!  Ick!!!!

@Searril -- Yes, "telephone witnessing" and "letter writing" are two very common forms of preaching now, especially for those who cannot go out door-to-door.  They use gated communities or apartment complexes where they cannot get into as one type of "territory" to call/write to.  Or as was mentioned above, they will also keep not-at-homes during the door-to-door preaching and give the addresses to a group to call or write to.  Calling/writing specifically to DNCs is new to me, but I wouldn't put it past them.