The following is from Section 4.c.(4) of
Southwest Airlines Co. Contract of Carriage -- Passenger Seventh Revised Effective October 13, 2011 [warning - the link is a .pdf] (
emphasis is mine):
"Delays or Involuntary Cancellations.
If a Passenger's scheduled transportation is cancelled, terminated, or
delayed before the Passenger has reached his final destination
as a result of a flight cancellation, Carrier-caused missed connection,
flight delay, or omission of a scheduled stop,
Carrier will either transport the Passenger at no additional charge on another of Carrier's flights, refund the fare or the unused transportation, or provide a credit for such amount toward the purchase of future travel."
Although the likely intent of this provision relates to taking a later flight, perhaps any delay
should be sufficient to convince a GA to accommodate a standby request based on this provision.