Windows 8 and the needed email address

I just bought a new Windows 8 laptop for a relative and, in setting it up, noticed that Microsoft is now requiring that the user have an email address to login and use the machine. That made me wonder.

What happens if, sometime down the road, the user's email address goes dead? For example I just moved and lost access to my previous internet provider. Since I was using their portal for my email I will lose that email completely in a short time. I have been busy updating my email address all over the place but suppose someone with a Windows 8 system does not or can not do that?

There are 2 questions here:

1) What happens to the computer login, and access to Windows 8, if the listed email address goes away? And

2) Does that change if the login was made local to the computer? I would think that would break the connection between the login and the computer but I don't really know.