As long as you don't put a limit on couch fort building. :-)

We have a hard time limiting screen time because Ian wants to have his Mario Galaxy time, but then Sylvia ends up watching him play and maybe he calls Sabrina over to help out on a level. Then Sylvia wants to spend her time watching a movie and Ian comes by to watch part of it before wandering off to do Lego work. Then Sabrina watches Nova for something she's studying ...

Obviously sick kid snuggle time doesn't count against screen time, you're clear there.