EL PASO, Texas -- Federal law allows international shoppers to get a refund on the sales tax they pay with the understanding that the merchandise is going back to the foreign country the shopper is from. But one state representative says Mexican nationals are abusing the current system, costing the city and state millions of dollars. Texas is the only state in the nation that allows "manifiestos" without having to prove the merchandise has been delivered to Mexico. Manifiestos allow Mexican shoppers to take their store receipts to a U.S. customs broker, where they must complete a declaration form, called...