Subject: Re: [Bitcoin-development] alternate proposal opt-in miner takes double-spend (Re: replace-by-fee v0.10.0rc4)

From: Matt Whitlock <[email-masked]>
Date: Sun, 22 Feb 2015 08:50:30 -0500

On Sunday, 22 February 2015, at 2:29 pm, Natanael wrote:
> In other words, you are unprotected and potentially at greater risk if you
> create a transaction depending on another zero-confirmation transaction.

This happened to one of the merchants at the Bitcoin 2013 conference in San Jose. They sold some T-shirts and accepted zero-confirmation transactions. The transactions depended on other unconfirmed transactions, which never confirmed, so this merchant never got their money.

I keep telling people not to accept transactions with zero confirmations, but no one listens.