SAN FRANCISCO — It’s always dangerous to cite unpublished decisions to the U.S. Court of Appeals for the Ninth Circuit. It’s a particularly bad idea when there’s contrary, published authority on the books. And it could be a very serious problem when you already face the possibility of a $2.5 million sanction.

That’s the predicament Dean Dickie of Miller, Canfield, Paddock and Stone faced on Friday when he tried to argue that the Black Eyed Peas’ recording of “I Gotta Feeling” violated his client’s copyright.