My job in school was to make 'A's ... hs & college. I was a self-learner with a high apptitude... had a few professors who's classes I would not miss.... ever. My degree was in Computer Science and Quantitative Analysis. If I had to teach a professor the finer points of 370 Assembler then I wasn't too concerned with being late... and I didn't give a rat's if he had a PHD in maf.
If the prof was tardy.... I think they got 10 min... 15 for a PHD. If they were a grad student then I probably wasn't there to even notice