This is easily done by allowing one faction of the two-parties involved in an Ebay transaction to manipulate not only who is to receive feedback, but when to dole out feedback through a simplified form of extortion, and in the process covertly set a standard that reverses feedback decorum. Whereas, when the seller takes receipt of payment and releases item to the customer, he is by this very act acceding that the "buyer", the customer has met his obligation in full. Whether voluntary or not, there is no legitmate reason for the seller not to leave feedback for the customer at this time. There are excuses, but no legitimate reasons.

  The customer, or buyer, is always last. He does not receive goods or services until he has paid for them. As this is the typical chain in the process of goods & services being bartered, or bought & sold via Ebay this should also be the requiste procedure when leaving feedback: seller first, customer last.

 But by virtue of Ebay's ambiguity and trying to court both buyer & seller it waffles, or fails to take a stance on the subject of who is first & last in the chain. If you read Ebay's feedback tutorial you will note they are quite specific in all other guidelines relating to feedback with a yes, or no, except for who should first leave feedback by trying to placate sellers by saying in their tutorial that "some" sellers feel the transaction is not over until they say so, and thus do not leave feedback until then. Technically, there are two transactions taking place. One with the seller, and another with the buyer, but the simple chain of events should still dictate who should be first, and who should be last..

  Unfortunatley, for the customer, Ebay has allowed "some" sellers to corrupt the process by hijacking the system with a simplified form of extortion using programmable software and turn the process completely on its ear. Although not in direct violation of Feedback in Seller Terms & Conditions that prohibits "Any conditions that limit or restrict the buyer from leaving feedback" the programming of software requiring the buyer to leave feedback first is not only a form of restriction, it is by it's very nature, a simple form of extortion, i.e., in order for the buyer to receive already earned feedback he must first purchase it from the seller. The price, or fee charged is the buyer must involuntarily surrender his respective order in the feedback chain.. Once this system is set up the seller can effectively manipulate the customer and in effect enslave the system. Sharecropping might be a more apt anology, Massa' gets his befo' we gets any!

  If software can be programmed to recognize & respond when a transaction has been completed, it should also be able to be programmed to leave feedback upon receipt of payment. By virtue of it's inaction, Ebay is not only condoning this practice, it is abetting "these" buyers to control & manipulate the feedback system. Point if fact. Even if the customer, the buyer, contacts "these" sellers and expresses his satisfaction and asks for feedback to be left for him the seller still demands his payment first. At this point Ebay feedback is no longer voluntary, it has been corrupted.

 Thus you have a simple review of how Ebay has allowed the feedback system to hijacked by the seller.