You don't understand contracts, an item has been offered at a certain price, a contract for that item is IMMEDIATELY formed when a purchaser indicates (via e-mail in this case), not when the seller agrees to the purchase.
The purchaser can sue for breach of contract, as well as contact the authorities to initiate prosecution for fraud. I'd remove the item immediately. Criminal offenses are not trifling matters. Regardless of your position with respect to the war, I'm simply trying to save you several hundred dollars and a jail term.
Yeah, I'm gonna sweat that one. But I've removed the post having made the point that anyone can list anything on craigslist, and it doesn't constitute proof that it actually exists.