[Danimal16]

I HAVE NEVER SEEN A GROUP OF RIDERS DO THIS.

CVC 21656 specifies that slow-moving vehicles causing a queue of five or more vehicles behind them must turn off the roadway in order to allow the vehicles behind to pass them. Section 21202 explicitly states that cyclists are "subject to the provisions of Section 21656".

Turning Out of Slow-Moving Vehicles
21656. On a two-lane highway where passing is unsafe because of traffic in the opposite direction or other conditions, a slow-moving vehicle, including a passenger vehicle, behind which five or more vehicles are formed in line, shall turn off the roadway at the nearest place designated as a turnout by signs erected by the authority having jurisdiction over the highway, or wherever sufficient area for a safe turnout exists, in order to permit the vehicles following it to proceed. As used in this section a slow-moving vehicle is one which is proceeding at a rate of speed less than the normal flow of traffic at the particular time and place.
—California Department of Motor Vehicles, CVC 21656, Turning Out of Slow-Moving Vehicles^[14]