i don't think the problem comes from danger to oneself but danger to the snake.
i could absolutely get an adult boa off my neck or body if it was actually trying to suffocate me, but what is the cost to the snake? i would likely have to injure it severely. so it isn't simply a matter of being strong enough to prevent the animal's killing you. it's a matter of how much harm will come to the animal through so doing.
i did bjj for some time and am pretty familiar with chokes. my 500 gram ball python can nearly choke me unconscious (i let her around my neck and can feel the pressure building in my head as my blood supply is cut). a large boa could easily strangle someone. if it got around your neck with all its force you'd be unconscious in 7-9 seconds. if you're a small or weak person it is dangerous. that's why i cringe when i see youtube videos of relatively small looking people with their "pet" retics or burmeses that weigh over 100 lbs.
moral is you may have to be willing to harm the snake if you're alone with it. if you have more people around there is a greater chance that they can grab and try to uncoil it.
also keep in mind that if a snake (or anyone) has you by the neck and is cutting off your blood supply you only have (like i said) about 8 seconds on average before you lose consciousness. so it isn't only getting the snake off, it's being able to do it with the clock ticking.
don't ever let them coil around your neck if you do not have people around or are not extremely comfortable with them. it wouldn't always be a gradual wrapping. image how they strike prey. no reason they couldn't be on you as rapidly