I teach clarinet to grades 6-12. I also am starting to teach violin (which I also play), though I only have one student right now. I'm sort of a jack of all trades (when you are a self-employed musician, you gotta cast a wide net to make ends meet... haha). I don't recall my students saying much about my lack of hair (I know there's been a few comments, nothing negative, though i can't remember what they were). On some level, I hope that I can be a good example of a bald guy who isn't scary (unless they don't practice of course...) haha
However, one time in high school I was doing an internship at a dentist's office for a health care class I was in and a little kid told me I looked like Dr. Evil (I was buzzed to a 2 I think at the time... haha). I thought it was funny.