One theory says this practice came from knights lifting their visors when greeting a friend
furlong Which famous .... 
before that, no need for masks in the operating room germ theory;germ Make a ... 
says this practice came from knights lifting their visors when greeting a friend... [DOC] [TLE] Category: Hero Lore - Vainglory [PAR] The HUD on his visor targeted around Skye's face and identified her by name ... 
then jammed her elbow back into the throttle; the airjets switched on and lifted 
her off the ground.