They are somewhat more prone to handicaps, such as visual impairment. I was born prematurely, and have worn specs since l964. I don't know if this would extend to mental handicaps also.
Violence, rough play, sports, males go in for these activities far more than females. one could get hit with a baseball, etc in the head.. put two and two together.
I am not aware of this term, Maybe this is some form of safety device, say on furniture to prevent these people from certain types of accidents. Could not refer to a Gallows-Frame execution device,...