I agree with you, Mary. I refuse to do the card trick.
A few years ago, I went in to Radio Shack to buy an item that cost less than a dollar. When I went to the check out, the clerk wanted my phone number. I told him that I do not give my number out. He responded with, "I cannot make the sale without it."
I told him that I did not need the item enough to warrant given private info to get it. As I was walking out, he said, "Well, I guess I can bypass the computer and sell it." I kept walking.
I have not returned to Radio Shack since, though I have been told that they have changed the policy.
Call me paranoid, but I think it is no one's business!