Phrasing I haven't seen on a coupon in at least 35 years: "Don't embarrass your grocer by using this coupon without making the required purchase."
That wording was always peculiar to me. Did awkward scenarios with misused coupons used to play out all over America? Did grocers used to say, "Wait a minute! I gave you the discount it says on the coupon, but you didn't buy the two required boxes of Graham Cracker Sousaphones! This is so mortifying?"