guests can still view threads I believe when you enable the negative handling + action prevention. i did this with the read thread action. i played around with Allow Guests to Trigger View Actions Actions which occur for the owners of content when someone else views them could potentially be seen by guests. It is recommended that this is disabled should the owner log out and view their own content. Include Thread View And Attachment Download but they can see the thread if I enable it or not. tried with pingdom tools and as a guest myself.