Sliders can damage the engine or fairings, which are covered by insurance anyway. You're better off worrying about your own safety than worrying about cheap safety measures that may end up costing you more in damages.

• fact
  While damage to engine components may be covered by insurance, frame sliders are intended to protect the frame from what could be permanent damage, or even a total loss.
• fiction
  While damage to engine components may be covered by insurance, frame sliders are intended to protect the frame from what could be permanent damage, or even a total loss.