Chelsee,
The following are some "compelling reasons" to play in a lottery pool. It is an excerpt from the FAQ from Mario's Lottery Groups:
Is group play for me?
The following is an example that may help you decide. Say you just bought 5 Lotto 649 tickets for the next draw. The jackpot is $20 million. You meet a friend who tells you they have just bought 95 tickets for the same draw as part of a lottery group purchase. Your friend invites you to join the group by simply adding your 5 tickets to the group's 95 tickets. You cannot decide what to do, so your friend offers you the option to decide after the draw. You sign your 5 tickets and the group leader signs their 95 tickets and all 100 tickets are placed in an envelope. The envelope is given to an independent auditor to hold. After the draw is held, the auditor checks all the tickets and reports back to you and the group leader. There are two cases to consider. If the auditor reports that none of the 100 tickets won the jackpot, then your decision on whether or not to join the group is moot. But what if the auditor reports that one of the 100 tickets won the $20 million jackpot and now you are faced with the choice of whether or not to join the group. If you decide to join the group, then you are guaranteed to win $1 million. If you decide to not join the group, then you have a 5% chance of winning $20 million or a 95% chance of winning nothing. In other words, by not joining the group, you are effectively making a $1 million wager on the hopes of winning $20 million. Most people, when faced with that option would join the group and take the $1 million. There are very few millionaires even, that would make that kind of wager. If you are the type of person that would take the guaranteed $1 million, then group play is for you.
Does the above example ever happen in real life?
Yes, it has, several times. The Michigan Lottery sold a series of scratch tickets in 2005 and 2006 where the grand prize was a free trip to attend a live drawing for a chance at $2 million. The drawing was always held at a special event such as half time at a football game or a community carnival. For each special draw, there were only 5 finalists. Prior to the draw, the 5 finalists had an opportunity to meet. In many cases, the discussions revolved around the possibility of splitting the prize evenly among the 5 finalists. Michigan Lottery held these draws between 10 and 20 times. Every variety of situations arose. In some cases, there was no decision to split and a single person won the $2 million. In many cases, all 5 contestants decided to split the money and each person "won" a guaranteed $400,000 even before the draw was held. There was one interesting situation where 4 persons had decided to split but the fifth person decided not to. The draw was held and the group of 4 persons won. The fifth person was like the fictional person in the above answer. He decided to wager $400,000 with the hope of winning $2 million. He was either very rich or very foolish.