If they deleted the relevant cookies on logout then the problem would go away - I believe that's the crux of the issue, certainly for me anyway. Besides which,

If they deleted the relevant cookies on logout then the problem would go away - I believe that's the crux of the issue, certainly for me anyway. Besides which, your hot-linking analogy, while technically correct, falls down when you consider just how many sites have a 'Like' button on them, compared with how many sites are hot-linking you - and more importantly how many visitors those sites get. It's hardly an equivalent scenario.