it makes moving the sporran out of the way impossible.
Just a point of clarification, it may be a little effort but not impossible. Most sporran hangers have button snaps to slip them on and off a belt without undoing the belt. If you want to remove your sporran, just pop the button snaps and the entire rig comes off.

If you want to remove just the sporran, use the trigger snaps that attach to the d-rings on the back of the sporran.