I use multiple cameras. When I import, I use custom settings to rename filenames based on the storage card used with the camera that the images are imported from. E.G, when I import from my D600, I prefix file names with D600_, and when I import from my Canon EOS M, I prefix file names with EOS-M_. Given that each storage device has a unique identifier (e.g., serial number), it would be great if the custom file prefix could be associated with the storage device unique identifier (s/n). In my (selfish) case, I don't use the same SD card across in different cameras (i.e., I always use the same storage card in the same camera).