Whew a bit of overkill, you would need to see them coming from a distance. Personally I don't like anything that would cause pain to them. They are not BAD and I know how boring it is to have to go from door to door to save your soul. Don't tell Brenda Lee about this one LOL
I haven't had anyone come to my door since I moved to this small town in Ontario. I kind of wish that they would so I could preach to them..
When I was in toronto they were coming around every month. I had a intercom system there and always told them from inside without answering the door that I was in the shower ;-) I didn't know then all this stuff I have learned recently about all the deception and pedophiles.