Everybody here is psychic we all have powers that create a force field around us and our bikes while riding; best scratch prevention ever.
For you non psychic members aside from not using it; just protect the major places prone to scratches on a frame aka the top tube mostly from leaning on things during lock up; just get a top tube pad for it.
And if you are so scared just get 3 top tube pads to cover the down tube and seat tube...
