A question entered my mind as I was sprucing up my utility trailer. I
removed the strap hinges and closure brackets, etc. so I could clean off
the rust, re-paint, etc.

There are lots of mating surfaces where rust was present on both
surfaces, such as the back of the hinge plates and the trailer itself. I
started wondering what would happen if I used a wire wheel to get the
rust off one surface, but not the other. (That's not my plan, just my
thoughts as I was working.)

All other things being equal (weather, moisture, etc) as they would be,
does the mere presence of rust on one surface make the other surface
more apt to rust?