Thanks for posting the link to the NTSB report. It's really worth reading closely.
I'm still not sure what the operational error was here, the only thing that springs to mind is that minimum lateral/vertical separation of two targets in the Bravo was not maintained PRIOR to the Cessna pilot accepting visual separation.
That makes sense based on the report from UAL of seeing the Cessna "turning hard..." In other words, the traffic point out was essentially pretty late in the game.
Reading the report, it basically implies that nobody was really paying attention to the transitioning Cessna. I'm not easily rattled, but THAT is an issue. The recommendations at the end of the report are actually reasonable. They mention the possibility of a standalone freq for handling GA transitions, similar to what LGA and EWR have. I have used the LGA/EWR VFR tower freqs, and they are awesome for several reasons.
I've also used the SFO twr freq when transitioning, and on two occasions, had to circle over Bay Meadows while awaiting a break on the frequency to get a word in. Thankfully, they knew I was coming (coordinated by SQL tower ahead of time). Had they not known I was coming, a cold call would've tied up the frequency for a relatively long time, during which time the tower would be unable to issue takeoff/landing/LUAW instructions to the heavy metal at SFO.
A standalone position makes all the sense in the world, I think, because transitioning SFO is _not_ always straight forward (there's no Silver Bullet routing that makes sense 24/7), and the tower is already busy enough.
All of that said, the Cessna pilot should've maintained better situational awareness. If you're southbound in the Bravo while transitioning SFO, you should have your eyes peeled on the 28's, watching for go-arounds, or departures. How the pilot did not know (apparently), that a jet had launched from one of the 28's and was heading toward him is a bit of a mystery to me, since he was on the same frequency.
SFO is a fast-running operation with the deps on 1L/R sneaking out in between the 28L/R arrival stream. It's not hard to imagine how a relatively infrequent operation (Bravo transition by a GA aircraft) would be forgotten.