Untraceable until the robber starts using it too. It is either useless to the robber, or traceable. If someone steals Satoshi's bitcoins and leaves him in a d

Untraceable until the robber starts using it too. It is either useless to the robber, or traceable. If someone steals Satoshi's bitcoins and leaves him in a ditch (so that he can't tell people they were stolen), as soon as that somebody starts spending them other people are going to start looking for him (mistaking the thief for Satoshi, at least until they connect an identity to the coins.) However this does not afford you any protection from robbers that believe, mistakenly or otherwise, that they can clean the coins in a mixer.