Park picnic rules – not allowed to set up for a picnic on one of the picnic tables?!?

Photo by PoPville flickr user Mr.TinDC

“Dear PoPville,

Walking through Kalorama Park today when I overheard one of the Kalorama Rec Center staff telling a woman she technically was not allowed to set up for a picnic on one of the picnic tables. The woman had laid out a tablecloth and a few plates to hold it down and was explaining that her family would be there shortly. The DC Parks lady was adamant that this was not ok, though she would allow it this time, and saying that permission needed to be asked, or maybe that she couldn’t set it up without others being there? Are there rules I don’t know about here?

I understand that we all have to share park facilities, and that sheltered picnic areas in Rock Creek require a permit, but to just use an exposed table for dinner seems fine. Is there a person limit? Is a permit require like if you’re going to serve food but not if you’re going to just sit there? I can’t find any rules on using the parks that would explain what is and isn’t allowed when having a picnic at a picnic table. Have I been violating some written or unwritten rule in the past when I have had a picnic with friends at those tables? What am I missing here?”