This is a quote from the book "On Zero Confirmation Transactions" by Chris Pacia
...And in the six years bitcoin has been going, this risk mitigation strategy has worked fairly well. Most bitcoin purchases are done through payment processors who accept zero confirmation payment s and the rate of fraud has been negligible.

This doesn’t mean every double spend attempt has been stopped, they haven’t. But we don’t need to stop 100% of double spends ― o
nly enough to remain competitive with credit cards, which currently have fraud rates much higher than Bitcoin. As Shapshift.io CEO, Eric Voorhees put it:

We accep...
read full book block explorer