I had an e-mail exchange with an electrician at the local permit office. I told him I am planning on running EMT through my workshop and planned on using the EMT as the grounding wire. He said that is allowed by code, but he "strongly recommended against it" because one bad screw will break the path to ground. Are these connectors that prone to failure?
If installed correctly they shouldn't loosen on their own. That said, my inspector too said he wanted to see grounding wires landing on the boxes in addition to the continuous EMT. Apparently, there are at least RUMORS of bad installs causing breaks in the EMT over time. I ran both EMT and the green ground wires, and ended up getting a different inspector for the final that said EMT alone is sufficient but he liked the dual ground paths saying "good, more is better for grounding"... There have probably been a few bad electricians in the past doing shoddy installs and those rumors keep the inspectors weary of using EMT for grounds unfortunately. In my OPINION, I think the continuous EMT ground path is superior to a simple wire tied by a single screw on each end; it provides protection, a fully encasing EMI shield and can probably carry more fault current than a 12 gauge wire.