On Fri, Jun 19, 2015 at 9:44 AM, <justusranvier@riseup.net> wrote:

> If we have ECDSA proof that an entity intentionally made and publicly
> announced incompatible promises regarding the disposition of particular
> Bitcoins under their control, then why shouldn't that be assumed to be a
> fraud attempt unless shown otherwise?
>

Making multiple incompatible versions of a spend is a -requirement- of
various refund contract protocols.

-- 
Jeff Garzik
Bitcoin core developer and open source evangelist
BitPay, Inc.      https://bitpay.com/