If you object to a little horse shit on the trails (Phew, oh how nasty! Yuck!), then consider how trails in the Sierras would be maintained without the pack outfits. Even the USFS and Park Service uses mules and horses to maintain trail systems.
A little history: local trails in the Bishop Creek drainage were originally created by pack outfits, who still help maintain those trails. The work wasn't and isn't done by the Sierra Club, that's for certain.
