I've been thinking about this bcc-Xela thing in its broader context. While I suppose you could technically say that a "deal" was reached (albeit, there is a slight bit of ambiguity here), I'm not sure how comfortable I am with using the PL mechanism to force a buyer into completing a deal while the deal is still in its initial stages (I can see buyer failure as PL-worthy if the seller waits for a buyer on a clearly defined deal and loses money/opportunity, like with a hot book or something, but I don't see that here). I'm not saying Xela did or did not screw up here, but....
Rhetorically:
@bcc: What are you really "out" here? A little time and aggravation from a PM interaction and checking postage rates? Do you really want Xela to buy books he's decided he doesn't want? Do you have a return policy (if not, why not)? What if you "force" the transaction, ship the books to him in the UK, and then he decides to return them to you? Why bother? Is the PL really necessary here? Why not just put Xela on your personal list (if you think that's appropriate) and move on?
Generally, it seems that the spirit of the PL "transaction failure" condition applies to transactions that are agreed to without ambiguity and then reneged upon, resulting in someone losing monetary value. Usually, I think this applies most clearly to seller failure, like when payment is made by the buyer and seller subsequently fails to perform. As I allude to above, the circumstances where buyer failure "should" result in a PL nomination seem harder to come by, especially when you think about practical return policy implications.
Applying these thoughts to the bcc-Xela situation...unless I'm missing something, I don't see it as PL-worthy...more of a personal mess list thing.