18. Sally Johnson lives in Baltimore and does business with a large, national brokerage firm. When she sends the broker a check, she mails it to a local address in Baltimore. However, when she receives a check from the broker, it comes from San Francisco. Her sister Joan lives in Los Angeles and uses the same firm. She mails payments to an office a few blocks from her home, but receives checks from an office in Miami. What’s going on? Should the Johnson sisters be upset?