...How do you determine if you're comfortable with the safety culture of a crew or boat BEFORE you begin your trip? (And don't forget that the RS1 passengers were assured there was a night watch.)
You wouldn't know before you begin a trip.
I mentioned that the only liveaboard that I went on that had a roving night watch and dedicated charging station was the Belize Aggressor III. On all other liveaboards that I went on, the crew went to their cabins/bunks and we didn't see them at night, and charging was done in our bunks/cabins down below. So clearly an unsafe culture is prevalent.
Doing the minimum necessary, pushing limits, and working "smarter, not harder" are human nature and prevalent in many fields.
As the Health and Safety Advisor for our schools, I'm quite familiar with cultures of safety - or not. They generally run top down, but like I said, anyone can shine during an inspection/check-in.
The way that I would determine if I'm comfortable with a crew or boat is to do research in as many places as possible, look at reviews and threads, see which names keep coming up, possibly talk to people who have been on that boat, and ask questions in writing. I would look at the layout of the boat and egress points. I would ask about centrally connected smoke detectors, accessible fire extinguishers, and emergency lighting. From the above, I would determine if I'm comfortable going on a particular liveaboard. More importantly, I would determine which liveaboards I would not be comfortable with in light of what we know now.
It would be impossible to know what happens in practice on every single "cruise", no matter what regulations, policies, and protocols are in place.