Jamboy,
If you were to add that to the Admin panel, then the PIREP would be credited to the Admin that is logged on. To credit another pilot, you would have to add code to all the files it takes to generate a manual PIREP, which then all pilots would have to scroll through to pick their ID. You can save/reject/edit and add custom fields in the Admin panel so to me, I don't see a need to alter the existing way of adding a manual PIREP.