Nice idea, but ultimately it is impossible to know if the customers in your store are resellers or people buying for consumption.
The way to prevent resellers from picking through your inventory for arbitrage is to correctly price your books from the start. With accurate pricing you can still undercut resellers and not make each book a commodity -- Resellers incur a multitude of costs: time, shipping, 15% amazon fee, etc. If you raise your prices to resaleValueOfBook - resellerCharges + $0.01, you cut out the combing by resellers and still offer a sizable discount from Amazon.com
The way to prevent resellers from picking through your inventory for arbitrage is to correctly price your books from the start. With accurate pricing you can still undercut resellers and not make each book a commodity -- Resellers incur a multitude of costs: time, shipping, 15% amazon fee, etc. If you raise your prices to resaleValueOfBook - resellerCharges + $0.01, you cut out the combing by resellers and still offer a sizable discount from Amazon.com