I'm using outlook as my RSS reader and don't feel comfortable appending my plain-text login credentials to the url...
"Click here to log on to your FogBugz account to access the RSS feed. If your RSS reader does not support cookies, add this to the end of the feed link to store your FogBugz username and password: &sEmail=youremailaddress&sPassword=yourPassword"
It appears that the RSS feed for Kiln activity uses some sort of auth token[?]. Does the 'case' RSS feed have a similar ability?