In all honesty, it was stupider than I’ve made it out to be. Her dad was well known enough that the surname should have at least begged the question of familial relationship.
But besides the family name in common, she occasionally taught from his books. AND she got her undergraduate degree from the program in which he was the head of the department. Back then, at least, it was one of the more notable undergraduate departments in the field, sometimes participating think-tanks alongside graduate level programs.
It would be akin to being a college football player and not realizing the Sanders or Manning you were standing next to was part it THOSE families. Or an actor oblivious to Drew Barrymore being a member of THOSE Barrymores.