Originally Posted by LumberJack

"Pass Travel Reminders
Be considerate of your fellow pass riders and airport agents. Do not list or activate on multiple flights. Cancel listings if your plans change. Jumpseaters, refer to your internal policy. Remember that nonrev standby travel is prohibited on any flight on the same day in the same market, same origin city, or same destination city for which a pass rider is holding or has held a confirmed reservation."

The JS he booked wasn't intended to be used and therefore blocks another pilot from booking it for their commute. That's exactly what the above policy is referring to. You're not allowed to book two nonrev flights, and you're not allowed to book two jumpseats (at least not that I can find, does our "internal policy" allow this?), so why would it be okay to list on AS while already having a DL booked jumpseat?
I always book the JS as my primary. If you miss the flight, call the company and they'll work with you to get you on the backup flight, that's the whole point of the commuter policy and why your backup should be on Delta.