When I log out of Area 51 using the "log out" link, I am logged out. But when I delete all the cookies of all Stack Exchange sites, I'm automatically logged in again when I visit Area 51 (but not other SE sites). How can I stop this? I want to remain logged out permanently.
I use Firefox on a Mac (most recent versions of browser and OS). There is nothing in localStorage, neither here nor under stackauth.com.