An added note about what does and does not happen in public in a Japanese classroom or in general... This time, about personal grooming.
It is very very common to see young women doing their make-up on the train. Now, I'm not talking about simply refreshing their lipstick or blotting their nose and forehead with oil absorbing paper (although both of those happen all the time), I'm talking about women with a large mirror propped on their knees running through their entire make-up routine - including curling their eyelashes with large curling contraptions.
I was still, however, surprised and very amused to notice a guy sitting in the third row of my class last week with a set of tweezers in his hand. Under the cover of the other hand held shielding the lower half of his face, he put the tweezers up his nose, jerked them back out, examined them to see the hairs he had removed, and wiped them off on his notebook before going at it again! I couldn't believe what I was seeing!!
Later that night, when drinking with my advisor (the professor of the class earlier that day), I recounted the story to him. His reaction, however, was one of respect for the guy who had been able to tweeze his nose hairs without reacting to the pain, rather than being annoyed about lack of respect or anything else!