Your experience with Mr. Rosenblueth (who was 30 years older, 70 pounds heavier, 5" taller, and had different colored hair and eyes) reminds me of my experience being confused for my boss. She is 5' tall, about 15 years older than me, several shades darker than me, has short salt-and-pepper hair, and dramatic black "Buddy Holly" glasses.
I am 8" taller (sometimes 10" when I wear 2" heels), have long jet black hair, do not wear glasses, and have a lighter skin tone. Yet multiple people still get us confused because we are both of Asian descent.
I guess people like Franklin just can't pick up on these otherwise obvious differences!