I always list for the jumpseat even when non-reving (even if there are plenty of seats in the back) just so I can preboard without selling my soul to the Ops agent. Whenever a CSA pushes back and doesn't want to list me (cause there are plenty of open seats and our new reservation system makes it painful for them to list the jumpseat) I always push back and say that the plane is one cancellation/unscheduled reroute away from being completely full. You think you hate listing me for the jumpseat now, just wait till there are 30 angry external costumers waiting in your line that also need to be put on this airplane in addition to me. I'm always polite and courteous though... just trying to get them to see it my way without any drama. That said, I always yield the jumpseat to someone trying to commute.
When I have no choice but to list for a cabin seat, I always walk up to the Ops agent, show my ID and offer to help with wheelchairs. That has allowed me to preboard every time I think... even if they didn't need help. If I am traveling with my family the Ops agent has also allowed them to board with the families after I have helped (or not helped if there were no wheelchairs). YMMV, but good luck.