Off topic but my Nikon F5 with the MF28 back will do leader imprinting too, IIRC. Not that I'm sending much of anything out for processing these days, but if I did I'd have to figure this one out. What the MF-28 back also does relatively inexpensively and well (and the F6 body does stock, w/o the back but rather spendily) is it can imprint your (c) first and last name in the margin between frames. Yet another reason to sleeve slides rather than have them mounted. To potential thieves, that's pretty fair notice that you take your work seriously (perhaps enough that you'll actively pursue copyright violations). Also, with this imprinting you stood a better chance of getting your originals returned to you from the wet-mount drumscan color separator guy after they were razored out out of the paper mounts, some weeks after the issue of the magazine was pasted up. (say what-what?)
Back on the original topic, Kodachrome in one of my camera bodies never scratched whereas E6 often did, something to do with the automated film transport gate. I finally figured out it was due to the Kodachrome RemJet backing being thick and sacrificial, it adds bulk to the film base but gets mechanically scrubbed off in processing. Another little factoid, did you also know that the reason PKR was more robust about holding it's color and grain structure than other color films in desert heat, is that the it's essentially B&W film until dyes are introduced during the processing stage?
If the processing weren't so hit or miss, I might still be shooting it... Also, for me, Kodachrome is dead. Long live Kodachrome!