But come on, if they have a do not call list they should respect it, otherwise why have it in the first place?
You made me feel sorry for the guy that came to your door first. It's probably not his fault. What usually happens in this case, is that indeed there is a note on the territory card that says "Don't visit this person".
But when a group goes out in a car, often there is one territory card and everybody pitches in, so the group leader will tell everybody " you do from house x to house x" and then report back with your notes. So when they go to your door, they don't have the territory card.
The group leader must have realized it and ran to the house but didn't get there in time.