Ok, found a couple of things.
First, I have checked in different browsers and all looking good. Again, visibility tag is very good and useful however this did show an issue (I believe) with snippets being visible when they are marked as "Only me". I have added to log.
Secondly, The search function when logged off does work to an extent. If I search for "By language" and select c# I get some search results. Cool, However if I select "View" I get the logon screen. Great. If I select popup instead whilst being logged off
I see the code regardless.
Lastly, The code is always visible if the logged off user selects something from the tag cloud.
I hope you don't mind me looking at this and reporting stuff? It's just I would really like to see this work as I fully support the work you guys do!