Years ago, Delta folks would take jumpseats on other carriers but not reciprocate because 'we don't consider it to be professional' as a JFK-ARN rider once told me.
Yes, reciprocal wasn't in the vocabulary. After 9/11, they were the slowest at returning
JS privileges. It took a threat of banning them from other carriers
JS leading up to the SLC Olympics to get DAL and DALPA to move on the subject.