As with the other query, Christine knew the credit manager would feel his way warily. Part of his job–equally important with preventing fraud–was not offending honest guests. After years of experience a seasoned credit man could usually separate the sharks and sheep by instinct, but once in a while he might be wrong–to the hotel’s detriment. Christine knew that was why credit managers occasionally risked extending credit or approved checks in slightly doubtful cases, walking a mental tightrope as they did. Most hotels–even the exalted ones–cared nothing about the morals of those who stayed within their walls, knowing that if they did a great deal of business would pass them by. Their concern–which a credit manager reflected–involved itself with a single basic question: Could a guest pay?

This is from Arthur Hailey, Hotel, 1965.

Linda Gorman covers this principle in “Discrimination,” in David R. Henderson, ed., The Concise Encyclopedia of Economics.