Our children were brainwashed into reverent stillness and silence whenever we watched a film at home, so by the time we took them to the cinema, I didn't worry about them not sitting still. But generally speaking, I agree with this sentiment. Ours were constantly outdoors, tearing around, running, climbing, etc. They're now 14 and 19 so we're rather past that era these days. But they still go out walking, riding their bikes, and aren't constantly glued to the internet or their phones (both of them have an anti-social media zeal quite unlike their contemporaries, and that's from their own personal choice I hasten to add, not anything we've insisted upon). :)