Great point, and one I've never really thought of. The type of terrain could very well influence your decision. Where I hike (Eastern US, mostly Ohio, Kentucky, Indiana, and Virginia), it's not a problem - though now that you mention it, I have seen a few scratch marks where a trail might run across bare rock for 50 or 100 feet.

However, more fragile terrain might react more poorly. Do you think that using the rubber tips (like Leki or Tracks have) would avoid the problem without negatively impacting the functionality of the poles?