I probably should add something to my earlier comments.
Many years ago, when I was at Uni, I did a bit of casual work going door to door doing market research; essentially getting people to fill out long surveys on the spot. We were given an extract from a number of extracts from street directories, and told what streets to do, within a period of a fortnight. This employer experimented, by, instead of paying an hourly rate of around $9/hr, it paid per completed survey. Well, of course, I planned my attack on each suburb to catch people at home, and pulled out every trick to get virtually everyone who opened a door to complete a survey.
I was effectively earning about $80 to $100 per hour, which was awesome for me at the time. I would finish my territories early, and go back to the office and grab more territories that other people (not as pushy as me) had retuned, and do them as well.
One thing I noticed was that I could only go in short bursts of a couple of hours at most. Once I got a little tired, and lost a little spark, doors were just closed in my face.
After a few months, the market research company went back to paying hourly rates, and so I quit.
The point is, JWs are door to door salesmen, and in my observation a lot of them are incredibly poor at it. I am not going to list what they should be doing (in case Borg spies are watching) but I can see why they fail so miserably.
Even though my first post was partly a joke, I am serious that if you want to “spoil the sale” or make sure the householder will have no interest in the message or joining the borg, there would be no better method than the one I described in my first post.