In which situation is rebating considered acceptable in shipping?

Rebating in shipping refers to the practice of refunding a portion of freight charges to a party involved in the transaction. The situation in which rebating is considered acceptable typically occurs when it involves returning a portion of freight charges. This can happen for various reasons, including promotional offers, adjustments of overcharges, or incentives provided to customers for future shipping.

It's important to note that while rebating can be acceptable in certain contexts, this practice must conform to applicable laws and regulations, including adherence to the carrier's policies and ensuring that the rebate is transparently managed. When a portion of freight charges is returned, it must be clearly documented and communicated to avoid misunderstandings or potential legal implications.

The other options present scenarios that either misrepresent the legality or appropriateness of rebating, as rebating is not universally acceptable, nor can it be done without proper disclosures and adherence to guidelines set forth by regulatory bodies and carriers.