[Random pet peeve: when a clearly-marked bike lane ends and combines into car lane, and still, bicyclists insist on filtering up the side of the curb up to the stop line. Please, don't)
The biggest risk is a car turning into you at the junction because you were in a blind spot. It's much safer to be at the front of the queue so you are clearly visible, and can clear the danger zone ahead of the traffic.
Also, in general, things you see cyclists doing that you perceive as dangerous very rarely are - almost every serious bike car crash is because the driver didn't see the cyclist and turned into them. The cyclist behaving most dangerously is timidly hugging the curb trying to stay out of your way!
Re filtering, is that technically against the rules? It's a single lane at that point, but in CA it's legal to share the lane if there's room. Seems like a cyclist or motorbike has the right to lanesplit and move up.
Yes, but in this case you filter on the driver's left. You don't filter up in the 10cm between the curb and the car when the driver is signaling right; it's a dick move and eventually you're going to get hurt.
I commuted in SF for a year, and I'd guess 75% of cars don't know why the bike lane starts getting dashed before an intersection.