Brian,

There wouldn't be a problem UNTIL something else goes wrong. When that happens it's possible for the voltage between hot and ground to change significantly from the normal 110v which could damage your KPL or even create a fire hazard.

I would STRONGLY recommend pulling a new wire to that box from some other source so that you'll have unswitched power and a real nuetral available. Pulling a new wire is not has difficult as it might sound.