There's going to be a standard set of return policies recorded in the system, that will be applied to both customers and vendors. The return policy for customers will be defaulted to the one setup by Customer Type, and optionally overriden per customer (should one be taken into account by Offer as well?). This can be verified on checkout through the web site, but also should be verified for phone, mail or other types of orders that are entered. The order also needs to record the return policy that it was taken under, as the customer's policy, or company's policies may change with time.