I can think of 2 reasons why an ILS facility might be uncalibrated. First, the flight check didn't happen in time, second, the equipment was U/S when the fligh check was due. As pilots, you won't usually know the reason and, in any event, you'd be wise to not trust it, if it is radiating.
I don't see any problem with dialing it up for a visual approach, so long as there are ways to cross-check it's indications so that you don't depend on it. There can, after all, be any number of problems with an ILS that's in this situation.