Do all permanent lighting fixtures need to be switched, per NEC?
The problem comes in with the type of fixture, a ballast requires a switch or local disconnecting means in the fixture depending on the type of construction.  an Edison lamp (screw in) would be ok. Having a light on all the time actually is ok by code but some fixtures like fluorescents that have ballasts require a way to disconnect the power locally . I would not be concerned in any occupancy to do this but label the blank plate where the switch was what it used to control. My personal preference would to be to add an occupancy sensor up at the lamp. Any movement turns the light on from 1 to 20 minutes on the models I use.saves power and I support several hundred in my plant and only have 1 or 2 a year fail in really nasty conditions.