Is this person's carelessness still none of my business?
How far are you willing to take that?
....that is the question.
Are you going to take a stand about the hot tub, the skill level, dehydration status? I don't really see myself getting into other people's business to the degree that I would turn my attention from my profile to theirs.
I might mention something, but that would be the most I would consider doing. Diving with a big group has inherent advantages and disadvantages. If you are on a liveaboard,
any number of things could abort the trip. People really seem to think they have more control than they do and if everyone is compelled to judge their fellow divers, ...well, how fun could being on that boat really be? (that is what I has kept me off liveaboards, really) too much like a school field trip. I know better than to put myself and others in that situation. I see DM's and Instructors in parts of the world that do not dive conservative or even safe profiles.
I watched a Palauan grab a tank under his armpit and drop off a wall almost 200 ft to catch a dropped camera for a customer, and then shoot straight up.
(am I going to lecture this guy?) No..I'll be amazed and realize his life, his need for a tip, his regard for his life, is different from mine. And what about all that beedle nut? Am I going to take that on too?
I honestly don't see how people travel with all their expectations. What about the newborns on mopeds with moms sitting sidesaddle weaving through traffic? The list goes on and on, and I think you have to just succomb to the fact that you are not in control of everything and worrying about yourself will probably keep you pretty occupied.