First off, I used the search and couldn't find anything specific to the issue of camera wear and tear related to using the cam as a video pass-through unit.

Any GL2 hardware gurus out there? If so, this question is for you.

I currently use my nifty boat anchor sized JVC SMPTE-C broadcast spec monitor for final preview & CC work for my productions (all SD). To get my NLE to output to the monitor, I hook up my second GL2 unit using 1394, then connect an s-video cable to the cam and to the broadcast spec monitor. I often have this setup turned on for tens of hours at a time.

Am I ruining the heads or any internal moving parts of the GL2 by using it like this? With the DV pass-through, I don't have to actually press "play" in VCR mode, so the cam is just sitting there sending images out to svideo.

As long as there's no tape in the deck, the heads aren't moving at all. Even if it's stopped in VCR mode, the tape isn't threaded and therefore not wearing on the heads.