Thank you for the replies.
So I will be able to stand by for later flights even if I miss the flight after checking in, yes? If so, if I ever miss a flight, I will probably be able to get a seat in one of the later flights as there are several flights per day and I will hit 1P within the month, and then 1K by Autumn..
BTW, what is SOL? If I am trying to get on a later flight the same day, would it make a difference whether I am checked in or not on the flight I missed?