Someone just found a way to "double-spend" in paypal.

[alani123]

This is why the protection against double spending bitcoin provides is something really important. Check out the articles below for more.

Detailed aticle from sophos:
http://nakedsecurity.sophos.com/2014/06/16/how-to-double-your-money-on-paypal-and-why-you-should-not-try-it/

The hacker's article:
https://cybersmartdefence.com/docs/Paypal-Safely-Double-your-Money.csd

And his website:
http://www.slacker.ro/

[🏰 TradeFortress 🏰]

This has been completely obvious to anyone with half a brain, and is an unavoidable side effect of reversibility (eg consumer protection) while giving merchants immediate access to their funds.