What is the point of check-in?
Why do airlines require you to check in?
It can't be to see that you've arrived at the airport ... because you can do it online when you haven't left home.
It can't be to make sure you're really intending to fly ... because you can do it right at the gate at the last minute.
It can't be so that they know what seat you're in ... because they will allocate that anyway.
It can't be to confirm allocation for upgrades etc ... because they already know who is flying.
So what does "check-in" even mean these days?