On: Cooperation among an anonymous group protected Bit...

[wmf]

A 51% attack cannot take other people's coins. It can only double-spend coins owned by the attacker and there's no way to do a 51% attack without people noticing.

[pcthrowaway → wmf]

A double spend would sort of be taking other people's coins though. Once you revert the first spend, the recipient loses their coins.

[vincnetas → pcthrowaway]

yes, but you cant take random coins from random walets, you can only take what you transacted recently.