I remember when I was nine years old, an offer for a "free trial" volume of a collection of Audubon's works arrived in the mail. I loved the beautiful illustrations and figured having just one volume would be OK with me, so I filled out the card and sent it off -- and made sure I canceled my "subscription" for the rest well before the required date.

Well, guess what happened... Volume 2 arrived about a month later. I duly wrote again, saying that I had canceled my subscription.

When Volume 3 arrived, I started getting concerned, and talked to my dad about the problem.

"Write again, and tell them you're nine years old," quoth he.

Never heard from them again...