My wife returned from door knocking and told me a householder claimed they were Wiccans and practiced witchcraft. The householder apparently said something along the lines that it probably wasn't compatible with my wife's beliefs.
Sounds like it had the desired effect. My wife agreed and moved on to bother other households.
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When I was a kid a couple of (I think) Mormons knocked on our door. At almost the same time, by coincidence, my uncle arrived. He summed up the situation and pretended to be a rival evangelist, stating lots of ridiculous benefits if I join his religion, not theirs.
After a bit one of the Mormons said something like, "perhaps we will return when there is a bit more maturity being shown", and they left. They didn't return, as far as I know.