They’re bringing cash. They’re bringing credit cards. They’re wipers. And some, Mexico assumes, are good people.Americans are going over the Mexican border in search of toilet paper and other household goods that are in short supply in the U.S., according to WKBN 27 News. They’re also going to Mexico for water.One Costco in Tijuana recently had a line of at least 600 people waiting for the store to open at 10 a.m. One shopper who waited at least an hour to get inside said she was in the market for “everything.”An Angeleno named Maria Castro drove more than two hours to shop at the nearby Calim…