Can I do a dual VOR check on the ground? I know that the regs are ambiguous on the subject, but does anyone have a good argument as to why or why not you can do a dual VOR check on the ground if the VOR signal is good?

For my particular situation, I'm at KRDM which is about six miles from the DSD vortac. There is a clear line of sight to the station, but the airport is a couple hundred feet lower than the VOR. 
Seems to me that a dual ground check would be fine since no flags are visible and the station can be identified, but I'm not sure.
Be careful performing a dual VOR check on the ground, especially if you are located near other aircraft or buildings that may interfere with the signal.  I have performed a VOR check on the ground at a few airports around the Southwest, and I have found that you can get erroneous readings, on the ground, compared to performing the dual check in the air. I would say its more accurate in the air.
As for how to log it. DATE, PLACE, ERROR, and SIGNATURE. Place, meaning the VOR station identifier. 91.171(d)