Lyft, SideCar and Tickengo — a trio of new ride-sharing app start-ups — were sent cease-and-desist orders over the past two months by the California Public Utilities Commission.

The firms have continued to operate their services since then, but word of some of the letters just came out in a San Francisco Chronicle story.

Lyft, SideCar and Tickengo make mobile apps that connect drivers to passengers who exchange donations for rides. The donations are only suggested, but riders who don’t make them risk lower ratings from the drivers. The PUC told the companies they lacked the necessary charter party carrier permits to operate.

Tags: sharing