The Germantown woman was loading boxes of food from the Manna food bank into a shiny sport-utility vehicle one recent afternoon when she was approached by a donor dropping off food. "What group are you with?" the donor asked the woman, who promptly burst into tears. With her Toyota Sequoia and quilted Vera Bradley bag, she had been mistaken for a volunteer -- rather than a client waiting to take home a bag of potatoes. "I'm a mother of four just trying to feed my kids," the woman sobbed to the donor, who was taken aback, then sympathetic. Such awkward...