Name that Price? Is taking a Seller on a Pricing Property Tour unethical?

Well, this has been the latest in several heated debates throughout our office.  Seems when times get tighter ideas push the envelope more. Based on a couple of videos we have seen around the office the idea of taking new Seller's or Seller's with stagnant listings on a pricing tour to play  "Guess that Price" has been an idea many have considered.  You grab your seller and several listings similar to theirs, tour them, and see if the Seller can guess the price of the other properties.  Generally, they can not and it gives them a lesson on  "market value" and home pricing in their area.  I know you are ALL thinking of which Seller would benefit the most from this game.

The problem, however,  some of us have is that we represent the Seller and agree to take  qualified Buyers through the home only.  Not Seller's looking to price their property.  You also have some Seller's that take hours to prepare their homes for showings and to take a potential Seller whose property could be in competition with theirs does seem to me to walk the line of unethical.  Not to mention not so nice. I doubt they would like this game?

Several agents have felt the real question is to whom do they owe more loyalty? Their actual Seller or the random Seller in the MLS?  Perhaps their loyalty should be with their lister so taking them through other MLS properties should not be a problem. 

I, who by nature like to keep the peace, suggest that an agent get permission from a Seller prior to bringing anyone not qualified to buy their home through their home.  Some Seller's are absentee owners' who may not care so their properties could be used in such a fashion. 

I guess I would wonder if my home was on the market would I want to have someone come through it for pricing reasons only.  My gut screams nope.  It is a great idea in theory but it make my feel uneasy.  Let me know what you think...