This is indeed tragic. She has not been found yet.
I am not trying to diminish the responsibility of any dive operation but...divers do have a responsibility to dive...responsibly. Diving alone...out of sequence with the rest of the divers...no BCD...maybe aggressive diving... can all add up to tragedy for the diver, and the boat.
I've been on the Sundiver Express a lot. They have ALWAYS run a top notch, safe operation when I've been on board. At the same time, I have witnessed several divers diving poorly (poor habits, poor pre-dive checks, no real dive plan, etc) on this boat and MOST boats I've been on.
Divers need to be responsible for themselves.
Where the right gear. Have a way to stay afloat when you are done diving. I always count on the boat NOT being there as a worse case situation. I carry a large SMB and, if diving away from shore (oil rigs) I carry a small, waterproof, VHF radio. Currents change rapidly in SoCal and you may not surface near the boat.
Do the right thing. I personally never jump off a boat until I see that I have been accounted for. When I get back on, I ensure I'm properly accounted for...it's my but on the line after all.
I hope we can find her. Her family needs to know.
Godspeed Laurel