I've heard of it, but never seen a leash with a ribbon on it. I think harnesses with velcro patches that state some of those things is becoming common.
A bit OT, but for decades this approach has been used in the horse community. If you see a horse with a red ribbon in his tail, that means they tend to kick, etc....
https://answers.yahoo.com/question/i...2184259AAsO6XU
It works well in that community.