So, Microsoft has indicated in the Windows 10 EULA:
“The software periodically checks for system and app updates, and downloads and installs them for you. You may obtain updates only from Microsoft or authorized sources, and Microsoft may need to update your system to provide you with those updates. By accepting this agreement, you agree to receive these types of automatic updates without any additional notice.”
May be this not a bad thing as many of the computer problems that come up are from unpatched computers. However, there has been numerous occasions where a Windows update (especially for third party hardware drivers) has broken the functionality of a device or worse the entire operating system. So mandatory automatic updates may not be such a good thing here. Users can opt to go on the ‘slow ring’ which will delay the updating for about a month after the update was released to the ‘fast ring’ (gets the update almost immediately). This would hopefully be enough time for Microsoft to address an issue discovered by ‘fast ring’ users and get an updated patch for the ‘slow ring’.
Now, about the ‘or else’ part. Microsoft still has not confirmed what would happen to users who fail to keep their machines updates. Back in April senior Microsoft product marketing manager Helen Harmetz said during a Windows 10 webinar
“…users who did not install updates within allotted time periods “will not be able to see and consume the next security update” “
So Microsoft’s attitude is a machine without out the latest updates (this includes non-security updates as well) is an unsafe machine and forcing the updates is for the user’s own good (until the said update breaks something including Windows itself).