The city known for random, public, counterculture events is considering clamping down on them.
The San Francisco Chronicle reported Monday that because this year's Valentine's Day pillow fight was such a mess, city leaders want organizers of such events to manage them better. If they don't that could mean shutting the events down.
The city is well known for its drunken Santas, large groups of cyclists, zombie marches and pie fights, among a long list of others.
These events are loosely referred to as "flash mob" in nature, partly because they involve large amounts of people and appear out of nowhere, often at random locations.
San Francisco city officials said there was so much trash left after the pillow fight event that the city spent thousands of dollars cleaning up the wet, sticky feathers.
The promoters of the event, now in its fourth year, must take responsibility for future happenings or "otherwise we are going to have to find a way to shut it down," said Lisa Seitz Gruwell of the Recreation and Park Department. One of the ideas floated involves applying for permits.
Many of the events are organized via text messages, word of mouth or Twitter.com.
They often have no identified leaders or sponsors.
Somewhere between 1,500 and 3,000 people participated in the pillow fight this year, the Chronicle reported.