Buddy separation is a mistake by one or more divers. The entire buddy or standby system depends on being able to monitor the diver 100% of the time. If that doesn't happen the system has failed.
I'm new to this thread, came across this post and I gotta say.. with the end of the year rapidly approaching this one immediately climbed to the top of my "top 10 list of absurd posts" for 2022.
This guy is either a non diver and/or troll or just really freaking ignorant. I'm leaning towards troll because of other inflammatory statements by the same person but whatever.
If you look through a camera lens or take a peek at your spg your attention isn't on your buddy. If you look at a pretty fish or shine a light under a ledge your attention isn't on your buddy.
If you monitor your progress along a coral reef or a swim through or inside a shipwreck and you take a moment to glance at the structures you're swimming near or through or in between so as not to crash into them, you're not monitoring your buddy. Especially if *gasp* one of you goes around the other side of a coral head or enters a wreck through a different opening or briefly enters a different compartment to take a peek.
If you're trying to get a tickle stick behind a lobster as you coax it forward to catch it in a net, you're not watching your buddy..
If you're looking for the boat as you approach your entry point, or you're navigating with a compass- you're not looking at your buddy.
If you're working with a reel and smb to deploy it at the end of a drift dive, your attention will not be on your buddy.
ETC ETC
There's no such thing as 100% buddy monitoring unless you stare at your buddy throughout the entire dive with an unwavering gaze. And don't blink or even think about clearing your mask!
Oh and I feel bad for the guy who got convicted for the death of his buddy. I just took out my SDI Solo card and gave it a big fat KISS.