>
> If you sent the Payment message and the server goes silent after receiving
> it, you retry to delivery.  However, the merchant can broadcast the
> transactions and force them into your wallet anyway. You could, quite
> likely, pay and never get an ACK.
>

No retries. If there's a timeout the wallet will consider the payment not
made, and if the merchant broadcasts anyway, the wallet will see the
transactions and sync with them correctly. The ACK is not particularly
important in the current design, so that's no big deal.

If we see this situation crop up routinely we can take measures to improve
things. I doubt we will.