I wrote this in my reply to Mark on another branch of this thread. Agreed-upon rules seem the most fair:

“contractual agreements would help solve this: “I will sell you this content only if you agree not to redistribute it”. In that case, both parties have agreed on the terms of the transaction. If the buyer breaks the contract (ie burns 100 copies of the cd and sells them on the street), then the artist is entitled to seek damages.

Perhaps that’s the ethical boundary: civil litigation, not criminal penalty”