I doubt Satoshi would have been able to cover all his tracks.. Something like this is easily overlooked, besides, I doubt he was trying that hard in the beginning..
This could be right.
If he was sure he covered all his tracks then he wouldn't disappear.
Or, he would at least himself make a formal statement that he was leaving
(https://bitcointalk.org/index.php?action=profile;u=3;sa=showPosts)That last post of his sounds to me that he still had lots of work to do on Bitcoin....