Before I leave my house I ask myself, "shall I take my camera". In a sense, I start planning whether I'll capture the moment long before they happen. Then I decide whether I'll take video or photos. Doing both often means you get neither to your satisfaction.
If I do decide to film (and that includes using my iPhone), my camera is always in my hands, ready to film. Which is why I decide before I leave whether today is for filming.
So it's not really about switching the camera on, but rather deciding if today is a day for filming. There are plenty of moments. You just have to consider whether those around you will embrace you filming on that day.