Did you see those enemies running around using /visor flipping their hood up and down at you? No? Didn't think so.

The problem lies within the use of the /visor command, I'm sure. What the players have and what they enemy has are two different meshes. The /visor command moves what's currently available (part of the mesh), and moves it accordingly. Simply put, unless the /visor command was adapted to swap meshes/models, it cannot be done.