This is happening to all of my sites today, if I am not logged in as an Admin. All I get it a bunch of gibberish code like pictured above when I visit my site.
I first noticed this happening a few days ago, when I was setting up two new sites and tried adding them to Google Webmaster Tools after I had installed WordFence. The preview images they were generating for the sites looked like those above - which had me worried, that Google's bots were not seeing the site properly.
Now that it is happening on all of my sites, I have no choice but to remove this plugin and try someone else's.
