This time of year, many people give and receive lottery tickets as presents.
If you gave someone a lottery ticket as a gift, and they won the big jackpot with it (let's say $50 million), how would you feel? Would you expect them to share some of it with you? How much do you think is fair? Would you be offended if they didn't?
And let's say you bought two tickets that day, one for yourself and the other you gave as the gift. You had the winning ticket in your hand (although you didn't know it at the time) and gave it away. Would you lose sleep over it?