All Your Cards Are Belong To Me Catan Strategy

I have been playing some Catan on XBox Live Arcade and if you want a few easy GamerPoints there is a strategy that can be played against the Easy AI opponents to make them give you all of their cards.

When it is your turn go to the trade screen and request two question-marked cards for one of any card you have. Then accept an offer if one is made. If no offer is made try offering a different card in exchange for two question-marked cards. Of course the question-marked cards refer to a card chosen by the opponent. Repeat this until none of the AI opponents will trade with you, upon exiting you will see that you have taken almost all of the AI opponents cards. This is only a fault with the Easy AI opponents, and I would class this as a fault because it does not convey a feeling of intelligence on the part of the AI.