A scratched card adds interest.
Now it has something that all of the rest of the cards don't have. Personally, I wouldn't take it to be a sign from the universe re: whether or not to continue using my deck if it got a scratch on it. But, I'm thinking that frayed edges, scratches, coffee stains, etc. probably add "character" to the cards.
On the other hand, I admit that I'm very protective over my cards and try very hard not to get anything on them. I'm very fussy about them. But, you know, picture perfect isn't always the way (very seldom is it) so if they get a little mussed or something, then I suppose it is rather like living life and being surprised that you broke a sweat, scratched a shin or cut yourself shaving, etc.
I find it interesting though, that you don't know how it got there.
I hope I remember that bit about "character," if something should happen to any of my cards. Now that I think of it, something did happen with one of the cards from my Golden Tarot. The cards stuck together and some of the color came off and believe me at that time, I was not a happy camper. I was just plain annoyed because I hadn't had it long. I'll take a look at it tonight (haven't used it in a while - not because of that, though) and see if it bothers me any. I'll look at it and think, "Now my dear you have a bit of character; instead of something lost you have something gained and it makes you all the more special." Yep! That's the attitude!
Blessings,
TL2