Whist I agree with safety measures ( within reason ), the reality is often VERY different from the experiences of people diving boats in clear water and in buddy teams. Add competition, dirty water, swell, tide, current and tide races into the equation and the picture is different. I'm not suggesting safety doesn't matter here, just that sometimes, even a float line, can be a hazard...
Dive in and under japweed and that line will tangle. Not might, WILL.
Add vis less than 2 meters. Cool, you are buddying and the diver drops down. Cool, but in 10 meters of water, in a tide, you are no longer above the diver as a buddy anyway. You simply cannot maintain a position over some of the spots I dive yet alone stay there for upto 1:15 - 1:45 to buddy a guy you can't see, nor will actually come up under you if you COULD stay put.
The dive world is bigger than the clear waters of the Med and southern parts of the USA, Bahama's etc. You make your own safety and, by definition, take your OWN, but hopefully educated risks.
YES, I have done AIDA training and NO I don't hyperventilate and yes I do maintain, as best possible, a X time UP, X time DOWN routine but you'll never completely eradicate the risks of freediving. Would we really want those risks completely removing ?
I wouldn't. I believe it's a wariness of these very risks that keeps me safe.
I will dump my float in a japweed bed, I won't hyperventilate, I don't overweight generally BUT, on occasion do. However, I ALWAYS use a Marseillaise style belt along with the vest and sometimes ankle weights but, I never go to surface, from ANY depth unless I've pulled at the buckle first. Not ever.
Would that help me ? Likely not as I cannot guarantee I'm going to be face up. I would like to be and I love the idea of the freedive vest but as yet, it wouldn't suit my weighting style nor budget.
In deeper water, yes, it would suit my weighting as I often just use a belt. In sub 12 meters or that 4 - 12 meter band, many divers use a more dynamic weighting locally of multiple belts, a vest, ankle weights.
In shore based comps, you don't have a buddy. I've never seen a comp where divers buddy up in UK or local competitions. So, despite tide, vis etc and all that jazz, divers aren't top of each other anyway.
I have never seen a B.O on such a short dive. I just don't see how any experienced diver could protect against a 1:15 B.O
Most divers I know don't even get started contractions on dives of that length or, they've just started.
I'm not suggesting it can't, or won't happen but there are, not 'excuses for safety', but reasons for not exercising the 'same routines' of safety that are dive location and style dependent.
There is NO no risk diving. Accept it, prepare as best possible and learn, gain experience, stay well inside 'known' safe parameters and what more can you do ?