As if you needed another reason. From the Chicago Tribune (thanks Beth!):

Ravinia Festival turf war, food fight hospitalizes Arlington Heights man, cops say

A dispute over lawn space erupted into a turf war that sent one man to the hospital before a sold-out Donna Summer concert Saturday at the Ravinia Festival in Highland Park, police said.

After setting up their blankets, chairs and a tarp, a group of concertgoers from Arlington Heights left for a restaurant. Returning an hour later, they found their belongings displaced by a Chicago group, which they confronted.

A woman in the Chicago group tried to attack a woman from the returning group, police said. A 40-year-old Chicago man then punched a 49-year-old Arlington Heights man, prompting a wine-and-cheese splattering melee, police said.

The Arlington Heights man was taken by ambulance to Highland Park Hospital, where he received 15 stitches, while the Chicago man was charged with battery.

Why do I miss all the action?

However, did the group that marked their spot REALLY need to use a blanket AND a tarp? Where they holding the spot for a small country? And then they all had to leave to get food? Really? There are unwritten rules when claiming your spot on the Lawn, especially for sold out concerts featuring a one disco diva. I think they broke both of them. However, 15 stitches are a bit much. Use your words, as my dad would say.

I believe both groups are at fault for dumbassery.