What would you say about this. The meter is directly opposite this panel on the exterior (typical 100AMP box w/no breakers). The cable coming into the panel is 4 wire but only three are being used to power the home. The extra wire is simply laying in the bottom of the panel. (It’s hard to see, but the gray wire that leaves the pic to the left, loops back into the pic at the bottom, and is tucked next to the edge. You can barely see the end of it in front of the knockout close to the entrance.)
Any concern?