I simply walk up, ask if they would like to give me half an hour of their time, and if they say no, I leave.
Like I said, I just don't think any one should do it, no matter how courteous a person is.
I might initiate the introduction, but they have to initiate the conversation that follows. It doesn't seem any different from stopping to help somebody change their flat tire, or delivering food to the poor.
This is a dreadful comparison. Those two things are utilitarian actions, conversion just isn't, if a person is unwilling, or doesn't desire it. I don't think you'll find many people who won't let you help with a flat tire, and poor people who won't accept food, if they really need it.
Well, most young children don't answer the door unless a parent is present, so while I don't think what you're saying is too important in regards to this conversation, you do have a point. However, I can assure you public schooling is not based entirely on fact. History itself is extremely biased, because it is written by the victor. Some people even believe the Pledge of Allegiance is a form of indoctrination. Public schooling also teaches children that rote memorization is the true form of intelligence, when that is clearly not the case. We're getting off topic though.
Like I said the young children example was a generalization, and had nothing to do with the door-to-door point. History can be biased, yes, but I think extremely is an overstatement. Fridge conspiracists don't exactly prove "public school is based on non-fact." Memorization isn't a form of intelligence at all, it's a form of knowledge. And honestly, I don't blame schools who emphasize memorization, what with the over intensity of test scores, and I think the public school system needs a reform, but you're right, this is off-topic.