I've been illegally cut off twice by them in San Francisco. I've been meaning to buy a bunch of safety cones so I can get rid of them...

That doesn't mean they won't do something sudden, freak out a driver/animal/pedestrian/cyclist/etc who then reacts and causes an accident. Just because they can see around themselves does not mean them making sudden shifts can't cause dangers for others on the roadway.

Indeed. I can leave the sudden moves for when it's life or death, but not on every move! Take time to signal, for everyone else to process, then go