I was approached by a very polite young man regarding gay marriage, and I agreed with him wholeheartedly, so we spoke for a couple of minutes. then he really tried to get me to give him money so he could "stay out there" doing the work. I'm totally for canvassing, but I don't think it's good practice to ask people for donations in front of a store because it makes the group seem a bit shady. Getting contact info seems appropriate, but he really tried to get money from me, and even after I said no several times, he kept trying. I think this tarnishes what you're doing.