I think I found a glitch but I cant reproduce it :)
I clicked on a link to post an article at the bottom of an article page and I ended up on this page:
I ticked the I agree button and clicked submit but it dropped me off in the homepage rather than taking me back to the url specified in the ReturnUrl querystring.
If I click to go to PostArticle.aspx now it just shows me the submit article form rather than redirecting me to the i agree screen so I cant do any further testing.
Is it a cookie, or a role I was added to or something like that?