Where a contract between a risk management firm and a printer was silent as to the level of security required of scratch-off cards, the printer could not be liable for defective cards.The 7th U.S. Circuit Court of Appeals affirmed a decision by U.S. District Judge C.N. Clevert Jr., Eastern District of Wisconsin.Sabafon, a telephone company based in Yemen, wanted to buy cards that would provide its customers with prepaid …