I wouldn't have such a problem with canvassers if you'd just learn to read body language. Your net casting really only manages to piss the people off who don't really want to talk to you causing a kind of knock on effect.
When I'm walking down the street on my phone, or earbuds in, I don't want to talk to you. When I'm sitting outside, eating my lunch and reading I DON'T WANT TO TALK TO YOU.
And if you think I'm going to hand over my credit card information to some idiot in a pink t-shirt then you're very wrong. Try to learn to read people better because what you're doing is not only invasive, it's rude and disrespectful.