This fall, the Harvard Cooperative Society promised thousands of students a 10 percent rebate on all textbook purchases. Few received the rebate. And the Coop blames us (the customers) for our losses. Welcome to Business Ethics 101--the Coop way.

In fact, less than half of those eligible took advantage of the rebate, which was worth hundreds of thousands of dollars in all. The money will revert to the store, which this year offered no other return to its members.

The Coop trumpeted its 10 percent textbook rebate as a guaranteed bonus for joining the organization. But the catch was that the rebate was only available between October 17 and October 31, and only to students who have saved all of their receipts and bring them in to the store to be processed.

If Coop managers don't think that asking students to collate all of their book receipts meticulously and wait an afternoon at the credit office constitutes an undue burden, then they don't know their clientele very well.

Store officials argue it's not their fault that less than half of all eligible students took the trouble to claim their rebates. They can't drag students into the store and push their money at them, they say. If Coop members don't think it's worth their while to claim their rebate, that's their business.

But it's not that simple. The Coop is supposed to want students to get their return on membership, not to turn the rebate into an obstacle course.

It is, after all, a cooperative; or at least it used to be. If members don't benefit from their purchases, then the store isn't fulfilling its purpose. So managers shouldn't publicize the rebate in a few campus newspapers, door-drop a few fliers and claim their job is done.

The means for ensuring that all members get their rebate are at their fingertips. They can simply add up each member's purchases, which are saved and itemized in the store computer system, and electronically credit ten percent of the sum to their account.

Such a system for guaranteeing the rebate is simple and efficient, and would save trouble for all concerned. The only possible reason managers could object to it would be that they don't want Coop members to get their money, that they use the unclaimed textbook rebates to subsidize their other, less profitable offerings.

Working to extract the maximum profit from each consumer is, after all, a time-honored way of doing business. But not a very cooperative one.