Blender ePMV & autoPACK: Units change to 'Metric' from default of 'None' upon loading

Why do the units change from None to Metric when loading ePMV or autoPACK?  I'm guessing this is a uPy thing needed to prepare for loading collada files.  Chris would prefer it stay on None, but he can live with Metric if there is some reason for it.
