The City Attorney of San Francisco has now sent three cease-and-desist letters to three electric-scooter venture-backed startups that are operating in the famed city-by-the-bay.

In recent weeks, San Francisco and other Bay Area cities have been inundated by a plethora of the dockless, short-term rental scooters. The scooters are accessed via smartphone app, typically for $1 to unlock and then $0.15 per minute afterwards. (Some have already ended up in Oakland’s Lake Merritt, seemingly in protest.)

Vice dubbed the new scooterscape a "bizarre scooter war," while Vanity Fair has called the phenomenon "Wheelmageddon." (One venture capitalist has even questioned how this is even a profitable business model.)

Just passed a guy in the bike lane:

Riding an electric scooter, going the wrong way, on his cell phone, without any night reflectors or lights.

Wearing a hoodie. San Francisco, I give you your mascot. — Hanae Rivera (@HanaeRivera) April 12, 2018

A few weeks ago, I had not noticed any electric scooters in SF. Now you can’t exit a building without tripping over one. — M.G. Siegler (@mgsiegler) April 2, 2018

Despite in-app warnings to wear a helmet and only ride in bike lanes with traffic, it is common to see riders about town routinely ignoring these suggestions.

In identical letters issued Monday, City Attorney Dennis Herrera told Bird, Spin, and LimeBike that their scooters were a "public nuisance" and that they must "immediately cease unlawful conduct."

As the San Francisco Municipal Transportation Agency informed you by letter dated March 28, 2018, State and local law currently regulate operating motorized scooters such as yours in the public right of way. Yet my Office has continued to receive numerous complaints from members of the public and City officials and departments about dangerous operation of Bird scooters. We have compiled documented evidence that Bird and its customers are ignoring the requirements set forth in that letter and violating both State and local law. For instance, customers are driving the scooters on the sidewalk, imperiling pedestrians and themselves. Customers are also leaving scooters in the public right of way, creating falling hazards and impeding the safe use of sidewalks, access ramps, and other facilities that enable persons with disabilities and seniors to navigate this City. Bird is not quickly relocating scooters that its customers have left creating these hazards. And customers are riding the scooters without helmets, putting themselves at risk.

The companies have been ordered to issue a formal response by April 30 and to address the "unlawful business practices."

Neither Spin nor LimeBike responded to Ars' request for comment.

However, Bird's Kenneth Baer told Ars in a statement that the company was taking the "concerns and recommendations... very seriously."

"In addition, starting [Tuesday], we will begin a pilot program in which all riders in San Francisco will be required to take a photo whenever they park their Bird at the end of a ride," he continued. "This will help Bird take action to ensure frequent violators of Bird's parking rules are suspended or deactivated."

Bird previously faced criminal charges brought by the city attorney of the City of Santa Monica (where the company is based)—it ultimately settled for $300,000 just two months ago.