I wish someone could explain the logic of the SW boarding system to me. I can't figure it out.

Why not just let you select your seats when you book like most other airlines do. If you book early you get the pick of the litter, book last minute and you should get the left overs. After all if you book early they have your money early, you should be rewarded for giving them your money sooner.
All this business of having to call exactly 24 hours before your flight or paying for EBCI (which guarantees nothing) is madness, and if you forget or call a little later, you and your family are punished and sent to the back of the line, just like in kindergarten.
If you look up stupid in the dictionary, it should define it as SW boarding procedures.
Maybe Disney should try that with their ADRs, if you don't call exactly 24 hours in advance to confirm your reservation, there will be no guarantee you will be able to sit together. Wouldn't that be fun.
I know it's comparing apples and oranges, so no Flames please

, but it would be just as stupid.
JMHO