Subject: Re: [Bitcoin-development] 0 confirmation txs using replace-by-fee and game theory

From: Gareth Williams <[email-masked]>
Date: Fri, 25 Apr 2014 14:51:23 +1000

On 24/04/14 22:07, Chris Pacia wrote:
> It would work but it's an ugly hack IMO. What do people do if they don't
> have extra to pay when making a purchase? I have 200 mbtc and want to
> buy a 200 mbtc phone but I can't because I need 400 mbtc. Sucks for me.

I don't see why it couldn't work with just 200mBTC.
* you sign a 200mBTC TX to me, walk out of my shop with the phone
* you immediately sign & broadcast a double-spend TX with higher fee
* my POS computer (or BitPay's) sees the double spend, immediately
spends the initial TX to fees, and sounds the shoplifting alarm.

You don't get any money back, but you do get an angry shopkeeper chasing
you down the street / calling the police / blacklisting you from the
store. Assuming my POS computer's behaviour was completely automated and
widespread - and therefore predictable on your part - why would you ever
try this?

The number of people irrational enough to try this /knowing it never
works/ is likely to be way lower than the number who just stuff the
phone in their pocket and shoplift the old fashioned way. So I'd be
comfortable without the extra 200mBTC collateral :-)