Let's say you need to show your passport and just have carryon for an International flight. You plan to get to the airport a couple of hours before boarding. Say you are a little delayed getting there and you are in the front cabin. So you are not concerned about upgrade offers. I've heard the argument that you should check in online so they don't give your seat away and I've also heard the argument that if the ticket is a flexible fare you should NOT check in on line in case your ride to the airport in involved in a crash and you miss your flight? What do you experts say?