So I'm a wheelchair user and need an aisle chair to board. A fair number of times, usually on an RJ, I never manage to get the GA to figure out that my seat assignment is completely impractical. They haul me on board the plane, the aisle chair guys and the purser *know* they'll never get me in to my assigned seat, so they put me wherever is convenient. Now I'm sitting in someone else's seat before s/he boards, I can't physically move to another seat, and it's kind of hard to explain that I'm not an evil seat poacher (at least not intentionally).

Any suggestions for my situation?