I feel the NEC should 100% prohibit the use of EMT as a fault path in lieu of a dedicated grounding conductor. There are too many chances for the EMT's ground continuity to be broken, and it could become energized. A dedicated ground conductor would be connected to the conduit system at multiple points (pigtails at junction boxes connected to grounding screw, for example) and dramatically reduce the chance that ground continuity would be completely lost, even if a locknut became loose or was removed entirely.
Just as using interior water pipes as a ground path is unsafe because of the possibility they could become energized if ground continuity were lost, the code should also view EMT without a dedicated ground conductor in a similar light.
[This message has been edited by newsgraphics (edited 11-11-2005).]
