This is a lesson that teaches the students how to manipulate data to achieve their goal. This type of data manipulation is done every day, the bottom line; to make money.
It is a very good lesson to teach students so that they would analyze graphs carefully before drawing conclusions.
I would change the lesson from water balloon catchers to something a little more creative or engaging, but the idea would be the same.
The commercial presentation can also be videotaped, so students can have a clear picture of misleading information.