They stood by as the group chanted and held signs, but that changed as soon as the activists lit up. Then, police rapidly brought the seven people caught smoking to a nearby tent for processing. Immediately afterward, the protesters became combative, chanting "bully," "ass----" and "Nazi," inches from the faces of riot police who slowly backed up as protesters advanced.
Then, less than an hour after they arrived, most of the activists had dispersed and no one was left in custody. By that time, the rain had stopped.
Event organizer Ed Forchion, known to thousands of Internet fans as "NJ Weedman," had waited for the marchers under a tree dripping rain. A tumor in his right knee made it too painful for him to walk with them.
"People keep asking me, 'Why do you keep doing things in Philly?' " said Forchion, who is from Burlington County. "This is a protest to the Feds, not a protest to the city of Philadelphia." Forchion uses liquid marijuana from California for pain relief and wants the federal government to recognize its medicinal uses.
The gathering has become a monthly act of civil disobedience, drawing people from surrounding states. Last month marked the first two arrests: event organizers N.A. Poe and Adam Kokesh. Poe attended yesterday's gathering, although he stood in the street because he is banned from entering the park.
While weed remains illegal in Pennsylvania, earlier this year state Sen. Daylin Leach introduced a bill that would regulate it similarly to the way the state regulates alcohol.
On Twitter: @glazerjessica