Yeah, but you pay the full fare with 1 person, half with 2 people, and it's free with 3+.

It's something that isn't straight obvious though. When I got there I also thought that people were just in violation of the people requirement.

I don't get the point of the occupancy reader if there's no hard-requirement of 3+ in the current zone. Maybe there are some stricter HOV-only lanes nowadays? I left the bay area in late 2023