Let`s us say that a exchange got hacked, Would there be anyway to ban those bitcoins? like blacklist the stolen coins so they cannot be used on the network? I know about going back in time with consensus of the network to a earlier block or forking and using that new chain, but could you just not ban the stolen coins? I mean make a way to do that?
Well it is defiantly has been made before or at least said that the addresses where the the stolen bitcoin was sent to were blacklisted when the Japanese exchange Zaif got hacked and over 60 million worth of bitcoin were sent to multiple addresses, but something tells me that the damage was already done and probably were sent to multiple address other the ones used for the hack and they just said so just to calm the media down and in reality they could not do anything about it, but who knows if it is true or not, we can't prove it.