Have you tried to call Crew Scheduling lately.... I just had a complete post on how well that works.
That said I had one DH that I called 24 hours out for the record locator and was correctly instructed to call back after midnight.
I called back and advised them that the locator was giving an error on Continental.com, stating it was a "reservation", not a ticket. I was assured that by early morning it would be corrected.
At the gate I was told that my "locator" was a paper ticket, and immediately called SOCC..... I made show time, and did not see my name on the non rev list, and made another call to Crew Scheduling, assured once again that I had a seat. so, once boarding began, I asked the gate agent if I could have a boarding pass..... and made my 4th call to SOCC, during the 20 minute hold I watched the jet depart without me. The agent even listed me for the jumpseat (on her own), which I requested she cancel out.... despite seats being available in the cabin.
As you say, had I boarded the flight I might have been out of position and/or re-crewed to a higher priority flight for my RA day.