HELP! I'm NOt Sure I Want This Bag

Here is what I have done in a similar situation...upon winning an item (not a bag) I strongly suspected it was not authentic after extensive review. I emailed the seller before I paid and said: if you have any doubts whatsoever of authenticity please understand that I fully intend to file all pertinent reports upon receipt of counterfeit items. Please, let's end the transacton mutually now before completion to avoid any problems. Guess what...they instantly agreed not to finalize transaction...they knew that I knew it was a fake and backed away and we were all happy.
 
^^ that is a good solution. I've always thought there is something different for some, not all, sellers of fakes about being asked directly to declare the authenticity of an item, especially when the question is asked in a way that implies the buyer is on to them.