. . . it seems unlikely that merchants would offer bitcoin discounts on the one hand but no corresponding bitcoin premium to suit new market conditions.
After reading over the replies to my original post, I realized that merchants might be induced to offer bitcoin-price discounts in a rising market and no bitcoin-price premiums in a falling one if they stuck to the non-reversibility of their bitcoin sales. In other words, a bitcoin sale would
always be final, no exceptions. This would be perfectly reasonable. Since they were paid in bitcoin, they are not going to refund in cash. And they are not going to want to hassle verifying your own bitcoin address, nor take responsibility because you inadvertently gave them the wrong one.
Maybe the first stores to really embrace bitcoin will be those whose customers have no choice but to search for discounts and yet who often pay premiums. Pawnshop customers come to mind.
Quickie Marts come to mind too. When you think of it, most of the stuff they sell -- gas (perfect for bitcoin), food, drink, magazines -- is not going to be returnable anyway, and near interstate highways most of the customers either won't be back at all or won't be back until they return from where they are going. And the knick-knacks are pretty much what-you-see-is-what-you-get. Quickie Marts are integral parts of the cash ghetto, and many customers don't even ask for a receipt -- they just grab, pay, and run. For bitcoin-sales paper receipts might not even be issued.
Pawnshops and Quickie Marts: two possible venues where bitcoin's inherent volatility could reduce prices for customers and costs for the merchant.