Question: Is it moral to take advantage of another person's ignorance? Suppose that I drop by a yard sale to see whatever is up for grabs. While rummaging through the junk for which the owners no longer see a reason to keep, I catch sight of an item which I know to be extremely rare and valuable. Would it be moral for me to pay the low asking price, then resell the item at auction for a much higher price, knowing that the owners are clueless about its value?
Question: Is it moral to exploit a design flaw in a government or private lottery? An article in Wired describes how a statistician noticed a design flaw in the Ontario government lottery "scratchers" game which would allow people to consistently win money. He was described as being "ethical" because he alerted the authorities rather than taking advantage of it for personal gain, and they fixed the problem. Would it be moral to exploit a mathematical flaw in a government lottery without alerting anyone? Would it make a difference if the game was the work of a private casino rather than the government (e.g., exploiting a bias in a casino's roulette wheel)?