> For soft babywearing carriers, the outlook is also grim. The kinematics of the baby, adult, carrier and airplane seat lead to crush injuries that are worse than the poorly restrained arm hold version.

The point is that the "return" - in a vanishingly tiny number of cases, the kinematics is very slightly better (maybe I buy that it is slightly better, without doing research, but it can't possibly be much better) - is not at all worth the "investment" - every single parent of every single baby on every single flight having to put up with a very real annoyance.