I've got a couple with serial #s, both bought on the exchange forum. I don't treat them any differently than any of my other GEC knives. When purchasing new I avoid the serialized knives because they add cost with no added value to me.
To the original topic - I generally don't carry my pocket knives and keys in the same pocket, so it's not an issue for me. I have user knives that get used, carried, and sharpened. So they get blade scratches, bolster scratches, patina, whatever. I am capable of polishing them back to like new if I feel the urge.
If I have a special knife that I don't want to get messed up but still feel like carrying for some reason, I'll wrap it in a small microfiber cloth before pocketing it. Usually that would only happen if I were planning on taking some pics of it or just fondling and admiring it that day.
When I carry a "pocket jewel" like that I always have a user along too. My knives, I carry and use or don't use them as I see fit.