What objects are going to hit you in the face?
Lots of little loose things in the cabin that people will not "stow" even if instructed -- iPods, Blackberries, books, toys, CD players, pens, glasses, shoes, bottles of water, hefty fashion magazines... Plus, of course, all the stuff that falls out of the lockers on the first bounce.
They may seem small and harmless but wait till one hits you in the eye at 100kts+