I don't know what a WSM is but, I've found a lot of knives in the field. I think orange, yellow and red handles could make a comeback as I have seen some for sale.
Yeah, I lost a knife before, mostly pocket knives. Pretty careless of me, so I got to useing lanyards when I can. Also, when I have the knife out and useing it, I'll always lay it down in comeplete veiw. Right in front of me and in the open, I haven't yet lost a knife that way.
As others have said, we have to take extra care of our stuff when we are in the field or we will lose it. Bright handle material could be spotted easier from a distance than black or brown, there is merit to brightly colored handles.
Still, despite handle color, people are going to lose knives.