I was actually trying to earn the Fanatic achievement, therefore on some rare days, whenever I am unable to connect from my PC, I connect from my mobile device, (Nokia 2700, Opera 6.0).
Now in the past, whenever I had to do this, later on in the day I got an scope to log in using my PC anyway, so there wasn't any chance of breaking consecutive log in.
Now several thing could have happened here, one is caching on my mobile device and the second is caching by Opera(they actually optimize every page request through their server and of course, caching could be involved). I actually opened the home page and then didn't do any activity. I verified that I am logged in using my account.
And to more confusion to all that, few days back I swapped open Id to my Facebook account, but my mobile device still had to old logged in session(using my Google account).
So, what actually did happen. I hope stackexchange would look into the issue of properly setting the number of consecutive days if they are able to find logs of my activity involving all the different accounts.