With the Monkey's Paw at one end of the line, the other end can be tied to a much heavier line. The Monkey' Paw can then be thrown from the boat to the dock, and the person on the dock can then draw in the heavy rope on the end of the light one.
Well I've been reading, "Yes! 50 Scientifically Proven Ways to Be Persuasive!", by Goldstein, Martin and Cialdini. It's a fascinating review of psychology research into how we make decisions. Chapter 14 gives an excellent example of the Monkey's Paw in action (albeit not specifically in a sales situation). More important, it gives a idea of why it is the technique works.
The book cites a 1966 experiment by Freedman and Fraser, in which residents of a posh neighborhood were asked if they'd be willing, in the interests of road safety, to allow a large and ugly sign reading "DRIVE CAREFULLY" to be mounted on their lovingly cared for front lawns. Not surprisingly, only 17% of the residents agreed.
Then an almost-identical request was made of a similar group of residents. However, two weeks prior to making that request the experimenters asked the second group if they would agree to having a much smaller sign placed in their windows. Almost all agreed to the small request. And then the number that agreed to the larger, ugly-sign request two weeks later? 76% - a huge increase.
The reason proposed for the dramatic change was that the second group of residents, by agreeing to the small-sign request, saw themselves as being participants in the cause of road safety. They were no longer simply sites for signs - they were good and upright citizens. Nothing has changed about the request -- it's the requestee's view of himself that has changed
The authors suggest that the application to sales isn't too difficult to see. Once someone has made a purchase from you -- any purchase -- they are no longer a prospect; they are a client.
As I say, a fascinating book, and worth a read.