Sgt_Kickaxe - 7:18 am on Jun 9, 2013 (gmt 0)
I mean Google will set several cookies the instant you visit the page including a youtube cookie and google+ cookie even if you are on neither of those services. If cookies are turned off when you visit the adsense login page and you then turn them on before entering you information Google returns a cookie error.
On WW the cookies aren't checked or set until after you press enter with your login info, which is more normal. Google does the deed when you first hit the site and I was wondering why since some may not log in etc. They don't wait for you to try to log in.
Try it out.