O.K. I want to state that I was paroled from 9E in early '08, but in my almost 8 years there it was a constant battle. Many factors contribute, but here are the biggies as I remember them.
1) NWA bean counters figured that the W/B issues would not justify having the weight installed in the tail cone and carrying an extra 50lbs for the life of the aircraft thus PCL RJ's have always had W/B issues. When pax weights were raised it really added to the problem.
2) Dispatchers are completely overworked and reluctant to spend any extra time on a flight no matter what the problem is.
3) Lots of short flights to business type destinations where most of the A/C pax are going out in the morning and returning in the evening and checking no bags. No bags in back make an almost impossible balance problem on short flights. MSP-STL used to be the worst for me and trying to get STL NWA employees find ballast for a PCL jumpseater was an exercise in futility.
4) PCL does very little of there of there own servicing at the gate or on the ramp. I am not sure if this is still the case, but getting people to just do their job was a constant battle, much less going above and beyond to help a jumpseater. You state the problem was in MEM which used to be better than the rest of the system, but that must no longer be the case.
5) I fought this battle daily for many years and did everything I could to get EVERY jumpseater a ride, and was usually sucessful, but on some days you simply cannot make it happen. I was also called in to the base mgrs office to be threatened about delaying flights for non-revs. I kept doing it anyway, but it still was unpleasant. When I was there MOST CA's would bend over backwards to accomadate a jumpseater, sticking their neck out in the process, but the deck was always stacked against them. Just remember MOST pilots are trying to help and not just ignoring you.