Seems that there are rules for where you queue for each of the ferries that depart from Gate E in San Francisco. Passengers for the Harbor Bay ferry service, to the Bay Farm island end of Alameda, must queue neatly around the edge of the water. Alameda/Oakland ferry service passengers queue down the access road towards Embarcadero.

Again, apologies for the photo – it is a cell phone capture, through a glass panel with the afternoon sun reflecting off of it.