Charging via pc with a cable that is for both data and power could always trigger a refresh. I had refreshes triggered even when I changed no files. Perhaps windows might be changing some tiny system files on the player? Desktop.ini files? if you want to be sure not to trigger a refresh, then use a power only cable when charging via pc, or use a cell phone charger, other AC usb charger, or usb battery pack to charge the player.
Charging without a data connection will also save the display from excessive wear while charging, and will charge the player faster than via a pc. Motorola or Blackberry mini usb chargers are very cheap now, perhaps even under $5?