All the ones I've seen got their icons removed with the generic tumblr one, (you know the square with the eyes or the cone) and if you click on them, you'll be promoted on dashboard to view it "this tumblr contains sensitive / adult content". Everything's still they're, just the icons look like the person has deactivated. Though one person I tried typing in the URL via address got the logged out screen version, telling me to go back to dashboard.