The entanglement itself doesn't have to be catastrophic event, the trick is reacting to it appropriately.
Absolutely. There's a concept I've heard, which is something like
"Stop, Think, Decide, Act (and repeat)
" In scuba, there is almost NEVER a reason to rush, panic, or act quickly.
For example, in even in perhaps the only "rush" scenario, being out-of-air , you're usually worse off if you immediately jump into action. You start burning through air faster, increase your natural propensity to panic, risk making the wrong move, and risk causing additional problems with frantic or imprecise movements (like entanglement, losing a mask, etc).
This video is a little long, but about half way through, the diver describes how he told himself (paraphrased) "I'm not going to make any movements, unless that movement has a specific purpose." The scenario he described was arguably more dangerous in any moment, than if you added up the danger divers are likely to face in hundreds of dives added together. Lost fin, lost regulator, lost buddy, lost visibility, lost guideline, and more.
Oh the number of times I've gotten the flag line wrapped around my foot/fin at BHB
I'm sure I look quite humorous sometimes getting untangled especially when it has gotten wrapped around it a couple of times. I refuse to surface even though the depth is so shallow. I see it as a challenge to my manhood to fix it underwater.
If you've got a backup plan, such as near the surface, you might as well. It's more like a safety-drill at that point.
glad you got out of that, never know what is in murky rivers
When diving zero-visibility, I often use a 2ft aluminum pointer to feel ahead. It certainly helps, but doesn't make me immune to entanglements or occasionally bumping into something.
Its good to practice entanglement scenarios. Get in a pool with some cheap string and wrap yourself up in it (or have a buddy tangle you) then practice unwrapping and using your cutting tools. Start easy, you can always make it harder.
Only do this with an attentive buddy ready to free you or provide air.
I'd add, do it in the shallow-end, where they can drag your head above water, in the worst-case scenario. A really bad entanglement could theoretically make air-share impossible or impractical.
A shallow non-rocky beach with little-to-no current or waves is also a good alternative to a pool.
Nearly 1000 dives and I've gotten entangled a couple of times. On monofilament fishing line. Fortunately it only hooked a fin on one occasion and the other it got hung up on a stage bottle swimming through vegetation. EEzy Cut to the rescue. I saw a couple of post about people going under lines, ropes, etc. NEVER go under a line if you can avoid it.
I also do a workshop on entanglements to illustrate the dangers and also show them that many times, by the time you realize you are entangled, it's almost too late. It's not as if it always results in you suddenly coming to a halt. You may swim for a ways before you realize it and when you do seem to be dragging something, people will often turn suddenly and wrap themselves up.
Situational awareness will prevent many issues. If I'm diving where fishing takes place, I assume there will be numerous places to get hung up so I slow down even more and keep my eyes open to as much as I can.
Another item to consider is picking your sites and buddies so that you don't raise the risk and if it happens, your buddy can help you out of it.
This is especially true with backmount (standard) configuration. Everything appears larger underwater, There are number of times where I thought I had more than enough room to swim under something, only to have my tank or regulators bump into the overhead object. I generally avoid any overhead environments, but when I do I always make sure I have plenty of exits, and go very slow.
Swimming under any sort of rope/line/cable is a no-go for me.