Isn't grading anonymous? Does he know your name if he sees you on the street?
Grading is anonymous (well, they grade the exams anonymous, but then have discretion to add points to people for class participation or whatever, if they've said they were going to). So what? I can't be mad at him just because it's anonymous?
My guess is he wouldn't know my name by face. But would recognize face. And would maybe recognize if I sent him an email.