I guess I don't understand the *why* behind a no-outside-food policy?!?!
Because many people make a mess, in addition to the comments here.
Yes, it is expensive to eat in the parks, however, in the good old days, people used to stash the food in a locker and when meal time came, used to leave the park and eat the food.
As to baby food, that has always been exempt from the rule, as has water and baby bottles. But, they do sell baby food at the nursing stations.
It is very annoying to purchase food and try to find a place to sit when you have many people eating outside food at tables intended for use by people who actually purchased food at the restaurant.
BTW, the guards are not there to check for food, their purpose is security, food, poses no threat. It is not their job, (nor are they interested), to "police" for food.
Coolers on wheels is really pushing the issue, IMHO.