Sometimes bags get left behind. It happens and it's hard to predict. Depending on the day of the week and the time of day your flight departs, your fellow passengers may be a hockey team with two big duffels apiece and a stick each, or a bunch of day-tripping business travelers with just carry-on. When the plane hits maximum weight or bulks out, that's it.

Lots of other things can happen: a misconnection at SEA between planes or a misload onto the wrong plane at either airport.

In any event, once a discrepency is noticed, your bags should be re-routed via the fastest possible path to your destination. Luckily, there are lots of flights between the West Coast and Hawaii.

My best advice is to pack a day's worth of clothes in your carry-on and hope for the best. There's really nothing you can do here but hope for the best.