How do Instant Credit Cards Work?

Currently what sales shop keepers do is that ask the incoming shoppers if they have a credit. If the answer comes as "Yes" well 'n Good, if , however the answer comes as "No", Salesmen do not waste time in making a Pitch for what they have to offer (in-store credit card offers).
The stores offer upto a lucrative 15% off in that day's purchase or if the shoppers are purchasing it online they get free delivery or a gift card.

However the problems is with Liar loans or bad debts. Those people who do not have the ability to pay. So the new ability to pay rule would be adversely affecting the instant credit system.