What are the rules? The rules are open for debate, but here are my ideas...
1. The first home run ball you catch, you can keep or trade. Do not ask for too much since a signed ball or bat and a photo is plenty. Do not ask for something from another player. It is humiliating to the player that hit the ball.
2. If it is not the first home run ball you caught, give it to youngest kid sitting around you. You already have one so give someone else the memory. Plus, karma will be on your side.
3. If you catch a milestone ball that breaks an all-time record, like the home run or hits record, then all bets are off. Sell it for big money, trade it for signed goods, keep it and put it on your bedroom shelf, or give it to the Hall of Fame. Whatever you want to do is fine. A ball like that could set you up financially for life. No one should decide that except for you. Beware of the consequences and backlash towards your decision though.
4. If you shove, push or bully someone that is smaller than you to get a HOME RUN ball, do not return to Miller Park. The Brewers do not need you as a fan anymore.
5. If you shove, push or bully someone that is smaller than you to catch a FOUL ball, please jerk your car into a bridge embankment on your way home. The world does not need you as a person anymore.
Any other suggestions?