There are two recent studies that underscore the danger to fans from foul balls. Gathering data from several major league parks and using a mathematical model vetted by five mathematicians and statisticians, journalist David Glovin estimates that some 1,750 fans are injured by foul balls at major league games every year. His findings can be found on the Bloomberg website at http://www.bloomberg.com/news/2014-09-09/baseball-caught-looking-as-fouls-injure-1-750-fans-a-year.html. When one factors in the number of minor league, collegiate, high school, American Legion, and other amateur games that are played each season, the danger to spectators is significant.
In a study entitled “Don’t Sit There…Or There…Or There: An Analysis of Ball Park Protection and Foul Ball Injury Risks,” published in the International Journal of Sport Management (October 2012, pp. 423-443), researchers led by Gil Fried at the University of New Haven (CT), confirmed that the field level seating areas along the first and third base lines are the most likely to have foul balls hit into them.