Does anyone need that?
By current implementation my moodle auto logs in guests if config auto-guest login is enbabled. On my site this results in a (totally) blank page such that the guest user has to browse back or renter the site url to get back to a contentful page. The point of annoyance happens to registered users whose session times out when they are on my moodle. If they refresh the page they just get that blank page rather than the login page.
A fix to prevent auto guest login in my moodle is very easy. If however anyone actually wants or uses the auto guest login in my moodle the fix would have to be by adding a config setting and hence a bit more work.
I'd appreciate any comments before I open (or revive) a tracker issue on that.