Also if you are using it for ladder type competition it might be frowned on especially if the creator of the shipset was also in that ladder or rolepay group. In big multiplayer games you might want to make sure one of the opponents wasn't the creator of the race before you start the game (in case you don't know the opponents well). They might have something to say about that also
. So far as far as I know no one that would limit single player use of their shipsets has made it available to download. Why would they make it availiable if they didn't want it to be used?
But its always nice if you like the shipset to drop them an E-mail to say so.