I usually turn this request around when it is brought up by a customer. I refer to the proposal as Pay IF Paid rather than Pay when Paid. I ask the customer directly what happens if their customer fails to pay, and I expand on this by noting that we take the risk. If their customer pays, everyone is happy. If their customer does not pay, we absorb all the risk and the loss despite the fact that we nad nothing to do with their credit decision making process.
One final comment: Under a Pay when Paid arrangement, your customers have no incentive and in fact they have a disincentive to do any credit assessement of their customers or to limit their dollar credit exposure. This leads to situations in which customers are shipped far more than they can reasonably be expected to pay, or situations in which your customer continues to ship even though their customer is past due and/or has broken payment commitments. Why" Because under Pay When Paid terms, your customer has NOTHING to lose.... at least that is how I see it.
Best regards
Michael Dennis