rss.c requires "okRead, okRdTkt and okRdWiki" in order to produce an RSS.

I want an anonymous user who can only read tickets and wiki to be able to get an RSS feed ... that is, I want the RSS to be useful even if I have restricted anonymous users to the minimum access.

From what I can see, "okRead" means the user can check-out.  This seems unnecessary to me for someone to simply get an RSS feed.