The Chicago Cubs fans are the primary ones who practice this, however other fans from other stadiums have followed suit.
The tradition began in the 1970's when a stage play "bleacher bums" was popular in the Chicago area.
The fans believe that it is cool to throw the ball back onto the field--they believe someone gives you garbage you give it back.
Well I say its disrespectful!!!! Don't you know any kid who would love to have a ball from a MLB team game? Even if you don't want it. Come on you can take the criticism from a few in your section cant you?
Some fans bring "decoy balls"--and after they catch the game ball--they throw back another they brought from home. IT'S STILL DISRESPECTFUL to me.
Here's a pic of a fan from Chicago doing the deed.
From WGN news
Am I alone in this? What do you think?