Id think that poorly using the vor/ndb would be more of a hazard then not using it at all, as would be the case in a navaid 'crash course'. NVFR (or cir for those inclined) seems the appropriate time to get up to speed on them.
Interestingly, I was told there is now no endorsement required for using navaids. So any pilot can use them at any time for navigation. Have yet to verify that for myself...