Joseph Dunninger is credited with saying, "Every time you add a prop to your act, your price goes down."
I can appreciate his sentiment; the ideal mentalist should demonstrate the ability to play with people's minds; not bits of paper or other irrelevant objects. With that, Ellusionist's release of The Informant is arguably a controversial one, because there are vastly mixed opinions of similar devices on the market. Many performers don't understand the logic or motivation of utilizing peek wallets. Often times, many performers deliberately avoid and disregard these devices for that very reason. Why should a participant write something down on a card only to have it hidden back in the performer's wallet? Why would a performer offer his wallet (of all things) to have something written down on it while his back is turned? Why would the performer have the spectator write anything down at all?
These are all valid questions that I always felt were glossed over in the literature supporting these devices. In my opinion, Dunninger's quote is only valid if people acknowledge that a prop was introduced in the act. If it's rendered invisible during the course of the performance, then you aren't harming to detracting from the notion of a "legitimate mentalist."
I figured I'd offer an opportunity for people to chime in and explain the pros and cons of using these kinds of devices, and more importantly (and creatively), actually expand upon how you as a performer would attempt to script the device into an act to minimize its importance/relevance/presence in a performance. In my opinion, to flatly disregard an item/prop/idea is not only easy, it doesn't offer any legitimate insight or critical thought. It's easy to be a cynic. I'm much more interested in developing solutions to actually make something work. So with that in mind-- if you had a prop designed to acquire information for the sake of mentalism; how would you go about scripting it into your work to take the heat off of its presence?