I just bought a new Nexus 5 after using a Nexus 4 for about a year.
After turning it on and using it at work, I go home and as soon as I turn the WiFi on the phone it connects to my home network without having to insert any password.
I have never used it before at home and I did not insert the password on that phone. To verify I went to a friend of mine's place where I had used the old Nexus 4 and tried again and voila' the phone connects to the network again.
Does anybody know if it's an expected behaviour or does it sound strange to you as well?
What could be the reason? The only thing I could think of is that Google is storing details about the WiFi you connect to on your Google account. Can anybody confirm? Is this even legal?