vocabularies

The governed set of who-bears-the-return-cost marks a return policy can state — free returns (no cost to the buyer), the buyer pays return shipping, or a restocking fee is deducted. These compose (a policy may charge return shipping AND a restocking fee), so they are marks on a many-valued qualifier, not one exclusive category. The FEE AMOUNT (a percentage or currency figure) is realised pricing data, not a member here (deferred to the fee-amount lane, L13). A growing set.

Answers the question: return fee responsibility.