I'm guessing that ,( and I do mean A BIG GUESS),that its a convience kind of thing, he would most likely have to box it up, ship it back to the maker, wait for the work to be done, which you all know that kind of stuff "seems" to take forever. The only other issue I could think of is that he could have possibly "burnt a bridge" with the maker. And isn't comfortable with sending it back, personally I wouldn't work on another makers knife without his consent to me from him personally. Meaning I would correspond with him myself, then I would make dead sure it was work that I am WAY MORE THAN PROFICIENT at, like something I do on a daily basis. If I was the least bit uncomfortable with it, I wouldn't touch it!
Thatt is just me, and how I see it, if my customer had someone else do work on one of my knives, I'm not quite sure how I would feel about it, if he was asking for something I didn't want to do, because I felt it was unsafe, then it would be on him and all warranty and guarantees would be void!
Which this is something I haven't thought of, AND is NOT covered in my warranty info, time to update it!
If it was a cosmetic kind of thing the customer wanted done and in no way altered the blades integrity, I'd be OK with that, but I would want to talk to the person doing the work, to make sure that they knew what they were doing, the best I could. I don't know its a slippery slope, no matter which way you look at it.
Just my 2¢'s worth, that's a pretty hot topic! The leather work is a nobrainer, sheaths are considered consumables as far as I'm concerned, (provided I made it), so I'd go for it on that one. I'm subscribed to this thread, really interested to see what other folks are thinking about this! Rex