Some additional thoughts from a soon-to-be former 1K who made that status flying 90+ Shuttle segments annually from 1995-2001.:
When Shuttle first started, they initislly copied WN's approach: flying standby on any discounted ticket required an upgrade to the YSHUTL fare. They abandoned this policy during the first year when they realized it made no sense to leave [unhappy] people at the gate and depart with empty seats at 8:00 a.m., only to have to DB people on the oversold 9:00 a.m. flight.
Only actual flight miles were earned on Shuttle flights -- the 500 minimum did not apply: LAX-LAS was 236 miles. This policy changed 1/1/2001 when the 500 minimum was implemented.
Discounted fares on Shuttle flights -- the fare basis codes ended with SX -- did not have a $100 change fee. [IMHO: if Starfish fares have the change fee, they will never compete with WN.]
I don't believe RNO-DEN was ever designated a Shuttle flight. I worked in RNO during the peak Shuttle years and these were always mainline flights. RNO-SFO and, later, RNO-LAX, were Shuttle flights.
[Edited for typo.]
[This message has been edited by Nevada1K (edited 10-10-2003).]