I had those S-s on the outbound bording passes of my trip last week from IND-MEM-LFT, but not on the return this week. Both trips were on Wednesdays. I wondered about it when I saw the "S-", and I received my mileage (and double MEM mileage) for the entire trip.

PS- I was not flying standby


(edited to add post script)

[This message has been edited by InIndiana (edited 08-26-2001).]