I've become so dependent and accustomed to relying upon my helmet mirror while cycling that I often find myself looking up and to the left as I walk down the halls of the school where I teach, attempting to look behind me for who is doing the talking, who is walking behind me (and what are they doing?!) In class, with my back to the general population, while I write on the whiteboard, I find myself looking up and to the right trying to see what the students are up to behind me. If I happen to mount my bicycle without my helmet and mirror I feel like my total vision is impaired and I notice its absence. I don't feel as confident on the bike without my mirror.
Do you think it would be odd for a teacher to wear a cycling helmet and mirror while he attempts to teach class?