Well... a cheaper, easier, and less legally ambiguous way of using fan expansion cards, with a higher guarantee of success, is to sleeve all of your cards. If you want to try out some new cards, sleeve the blank cards, print out the new card, and stick the piece of paper in front of the blank. I haven't played with fan cards, but if I did this is how I would go about it. Plus, your regular Dominion set will still look pristine after hundreds of plays! My poor, decrepit stack of Laboratories wishes I had done this.