Regarding colored fins: On a recent beach dive off SoCal in bad visibility, everyone in my group said they appreciated being able to follow my yellow fins and wondered why all fins aren't yellow.
Finally, this situation was tailor made for "good samaratins" as first-responders. If there were survivors on the surface or in air pockets (no chance given impact) their best chance for rescue would be from the first people on the scene be they surfers on boards, tourists on wave-runners or pink-finned ladies on their second post-certification dive. I didn't hear anything about some of the rescuers needing rescuing so they all did a good job.
Jim