When I was teaching (now retired) I always made sure never to be alone with a child/teenager. Teaching assistants were a godsend.
If unavailable, I'd meet/teach an individual child in a public space ie library. Noise/concentration was not an issue, because I found other children/teachers were aware.
My late father was a music teacher at two secondary schools back in the sixties and seventies and it was mostly girls that he taught. If he was giving any of them music tution after school as both schools had brass bands he would always make sure that the door was left open of the music room.