Andreas is incorrect here. A double spend _did_ happen.
Bitcoin's double-spend protection is probabilistic: after one confirmation, if the sender is attempting to double spend, the probability of success is extremely low. But it's still non-zero.
As the Bitcoin whitepaper helpfully explains, the probability of a double spend attempt succeeding drops exponentially with the number of confirmations. One confirmation is extremely low, two is basically (extremely low)².
Full details: https://bitcoin.org/bitcoin.pdf
Unfortunately, Andreas falsely claiming a double spend did _not_ happen is dangerous: people have to realize that a single confirmation is not an absolute guarantee.
This case was ~$20, and looks like someone was just moving money between different wallets.
But if you're accepting a payment large enough that you can't risk even a very low chance of a double spend, you _do_ need to wait for multiple confirmations. Claiming otherwise could lead to people losing money.
@pete peter, wouldn't you say double spend requires that a merchant was actually defrauded? no one accepted the deposit and credited the entity with the additional funds here.
unlike the okpay double spend in 2013 which really was a double spend.
@nic No I wouldn't, not from the perspective of users interested in understanding Bitcoin. A double-spend technically speaking happened. It looks like the double spend was between two different wallets, by the same person. But it might not have been.
Regardless, it's a good lesson learned to remind people of best practices.
@lucash_dev @nic My willingness to talk to journalists has dropped dramatically in general; Coindesk specifically I almost entirely stopped responding too due to badly reporting that wasn't getting facts correct. A year *prior* to Cuen's first article on the Lovecruft case in fact!
@pete fair enough. spend 30 min on the phone with a journalist explaining how bitcoin settlement works. probabilistic settlement is still a mystery to these people.