I know it's not good to have nylon on nylon when there's friction involved, but the rope has no reason to slide when rappelling in canyons (except maybe when you retrieve the rope - even then there's no load on it).
Leaving behind a bit of webbing for an anchor is necessary and fine, but the extra cash to buy rings is too much. Are there any cons or inherit dangers to rappelling directly off some backed up anchors made of 2" webbing?
- Blake