ForceFlow is right on the money.
I wonder if the fine print of the offer says the customer has to buy a 5D3 from them within a certain time of becoming available? If so, they're being very clever and it might be win win for them... if the 5D3 isn't announced they just made a sale If it does get announced, they'd take back the 5D2 and sell a 5D3 which would, at full introduction pricing, have a higher profit for the store than the current price of 5D2. They'd probably be able to sell 5D2 used for not much less than new and overall they make money in either scenario.