Several thoughts.
If a person is a solo diver......I will gladly dive with them no matter what size they are. I reserve the right to not get close if they are in a full blown panic...otherwise I will do everything I can. If they are of the mindset to take legal responsibility for themselves...then I think its great they are being active by being there and I will support that. I would not be any more troubled if they had a heart attack and died, than if they died watching tv or eating dinner..probably less.
If a person is a buddy diver, I consider who else will be present..because I am a "solo diver with partners" with a few exceptions. The exceptions are a few divers that are worth making an exception for. In that case..I go on their program, in order to dive with them. That's only a few people.
For me..this makes a big difference, the "mindset", as well as the physical aspect.
I haven't quite worked out the whole family aspect (they sue, not the dead guy). But for now, we have a conversation on our boat usually like this "okay..we are all solo here, right? everybody else witnesses everyone agreeing. So..we have witnesses to the agreement. I feel certain that will be worth something, in court. I think anybody should be able to dive under any circumstances, as long as they take responsibility for that. "We" will all function to the best of our ability, in rescue, even though we are "solo" divers.
This covers not only the overweight, but anyone with "issues"...because we all have something at some point in our lives.
liscense, etc)
I do not think we can any way, manage risk, if we can't accurately and empiricaly identify it and form decisions and judgments in a logical way.
Honestly, I find divers not the most logical group of people.
I was wondering why a very high percentage of tech divers seem so out of shape...they will hone their gear, but not their bodies. I think it is because 1) many are middle aged, and we are starting to fall apart 2) tech diving is largely a mental game...and selects for different people. The "athletic" people are out doing more physical things, and frankly, if you work full time and tech dive, there is not as much time to work-out.
They really need to make it part of their program and carve out the time. Some do, many don't. And yet they are very opinionated, because they often have the most knowledge...