I use USAirways to jumpseat quite often. I was having this issue 50% of the time with gate agents at a certain station. Finally one day I asked an agent who was helping me (who didn't ask me to list prior) why some agents say jumpseaters have to list on the phone? She said I am the station manager here and you don't list. As a matter of fact IF you list prior we cannot associate that record number with the jumpseat and CASS because an agent on the phone doesn't set up the record number that way. She said that they would just have to create a whole new listing anyway that gets associated with the pilot jumpseat request.