Remember when you were a kid and it was entirely acceptable to promise anything with no intention of following through-so long as you had your fingers crossed? Well, the oft-repeated phrase "with approved credit" is a merchant’s way of crossing their legal fingers. Some great deal is offered and the advertising is appended with that phrase " with approved credit."
This means that you, as the buyer, are required to show up with a squeaky-clean credit history and a high credit rating. If you show up with a tarnished credit history, why, then, the great deal is not quite for you (instead, how about this other not-so-great deal while you’re here and excited?). When you think about, this useful gotcha can conceptually be applied for your own reasons. Next time the teenager asks to borrow the car, you can always come back with "You sure can, with completed homework."