301 Moved Permanently: Harmful?

Hi,

As specced in RFC2616, the 301 response code allows the server* to  
arbitrarily and permanently change the configuration of a user agent.  
Thus anything from a temporary misconfiguration of the server to a  
deliberate attack can cause a bookmark or automated client to never  
work again (unless the user has backups). I'm shocked there's no  
verbiage in the spec pointing out this pitfall. Am I missing something?

(* or rather the currently connected network, since there's no  
guarantee you're speaking to the original server)

Graham