We know that once you sign up to Sky Q, your Sky+ Viewing Card is scheduled for deactivation at some point in the future, but if that had happened, you wouldn't be able,to watch any channel in your subscription package on any tv.
If,you have a second Sky box and a Multiscreen subscription, we've seen reports of the Viewing Card in a second Sky box being deactivated.
However, if your second tv is connected by coax cable and a magic eye to your only Sky box, there's no setting which Sky can change to affect it. It wouldn't stop working solely because you've signed up to Sky Q.
