On Fri, Jun 19, 2015 at 10:48 AM, <justusranvier@riseup.net> wrote:

> On 2015-06-19 17:40, Jeff Garzik wrote:
>
>> Making multiple incompatible versions of a spend is a -requirement- of
>> various refund contract protocols.
>>
>
> Is there not a dedicated field in a transaction (nSequence) for express
> purpose of indicating when a protocol like this is in use?
>

No.  You cannot know which is the 'right' or wrong transaction.  One tx has
obvious nSequence adjustments, the other - the refund transaction - may not.

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