If it were my bike, I would install a chain stay protector. If I use my bikes, they are going to accumulate evidence of that use whether riding or loading in and out of a vehicle. I have used nail polish for touch up on my Rockhopper and it passes the 6-foot test. White paint pen on my Specialized Tarmac. While I understand not wanting to damage a perfectly restored bike, I think it is a shame that something is too nice to be used but only admired. Different strokes for different folks.