You're always going to run into some parents that will freak when they hear their child's music teacher has a tat. If they really were that offended, they could pull the kid from the program. Thankfully, most normal people aren't like that. I think most parents would see it as a dedication to what you're teaching. After all, the word "music" isn't like a full body tattoo of guns or something haha.
Being a former band geek myself, it would be cool to see a normal conductor for a change. Mine was super mean and didn't believe in fun. That's not a good learning environment; having an open-minded teacher is.