Posters will (hopefully) remember my dilema recently, whilst in my LBS for some bits, I spied a spangly pair of Mavic Kyserium SL's priced at £149, I drew it to the attention of the assistant who assured me that they were priced right as the owner had told him they had two pairs to sell, I assured the confused assistant that he was mistaken, but if they stayed in the window at that price someone less scrupulous would happily take them at that price, shortly afterwards the owner returned, I asked him if the wheels were some sort of mega deal, he hurriedly removed the price ticket which clearly said 'Aksiums' on it.
I will admit to having a slight twinge of doubt about paying and scaperpering, but I wouldn't have been able to put them on a bike, as we often ride together and I think he would have twigged where his £500 stock/till deficit had occured, the next time he saw me on a club run, and 'Kevin' was sporting new wheels.
Honesty is always the best policy IME.