The requirement to remove the flint was clearly written by someone who knows sweet FA about flintlocks and how they are tuned.
Removing and refitting the flint requires test firing the thing to ensure the flint is correctly located and straight to the frizzen. That isn't exactly safe to to when the friggen thing is loaded. Personally when I have taken my flinter out hunting, I would blow off the pan powder and lower the #### on an open frizzen. A muzzle loaded doesn't get any safer than that.
Loading the cylinders at home and TRANSPORTING the thing to the range is NOT storage is it?