All the instructor where I did my CCW training used the colored floor plates. But this was for them to easily ID their training mags compared to their carry/SD mags. I was still confused then once we got into live fire I understood. With lots of mag changes and malfunction drills all four of my mags dropped onto the hard gravel ground many times. Sometimes mostly loaded with ammo. They took a beating and got pretty dirty. Now I understand the need to keep the mags separate.
