The D-Link DIR-615 has no logout option, and if you go to the admin URL's (e.g. 192.168.0.1/index.asp) at any time after logging in, it lets you in again without a password. This survives router reboots and even clearing browser cache and cookies. This is because the DIR-615 caches valid logins by MAC address -- i.e. if it's seen a valid login from aa:bb:cc:dd:ee:ff, it lets that computer have unrestricted access to the admin pages for a while (even if it changes IP addresses).