There's a little known policy concerning baggage and medallion members.
If a SM/CM/PM comes home or goes to their destination earlier and on standby and their luggage does not keep up with them, DL will bring it free to their home/hotel/office when it does get there.
The general rule is that if a passenger flies standby, then the luggage is their responsibility - they have to go back to the airport and get it. This, though, does not apply to elite members.