I happen to work with my father, and today we got into another debate about the origin of life. During the debate, while rebutting a lot of creationist canards, he said that mutations are always harmful to an organism.
After he left I sent him a quick email with a link to talk origins on the subject of mutations. By coincidence he called me up to his cubicle about two minutes later to give me another assignment. While he was explaning the task to me, I glanced at his open inbox on the screen. I noticed the email I sent only two minutes prior was missing. I asked him if he had deleted the email. He replied, "Yes, because i've already seen that website before."
I shot him a look of contempt and walked out of his cube shaking my head in disgust. This experience has proven to me that there is no point to debating a JW or any creationist for that matter, because as soon as you supply the evidence they so desperately require, they will delete it if it doesn't follow their preconceived notions.