"As nature intended". Ever touched those things? I think nature intended them to be used to moor oil supertankers. Also, wouldn't the poison darts pose a problem similar to the lug nuts?
Well, mooring supertankers IS a natural use, I'll give you that. But the poison darts aren't as heavy as lug nuts, so as long as you make sure the tips are buried in the hair, it should be safe.
As someone who used to have all of their hair braided up, you learn how to properly thrash about without whipping yourself in the process.
Most of the time, anyways. =p Depends on how enthusiastically you're thrashing.
Also depends on the length, number and position of the braids. And the torque, which in turn depends on how far you can rotate your head.
"Braided up" is fairly safe, Pigtails, however, can be very damaging to personal health.