Hi
Metallic is basically reflective pigment laying at different angles reflecting light if you rub it the pigment becomes loose. The same would happen with paint hence why they laquer cars. You can use a metalic which is suspended in a clear liquid but it does not have the intensity of loose pigment metallic and needs to be layed down very wet for the pigment to flow. It comes to the point of why would you want to rub a print, if its going into an area where it could get rubbed against then laminate
Kev