Is it appropriate to use [先生]{せんせい}, either by itself or as an honorific after their name, when addressing a ski instructor?
I'm not sure whether it'd be appropriate because:
- Using 先生 in this context may be disrespectful of other kinds of teachers, in that skiing instructor may be a less honorable profession than other kinds of teaching.
- It may be too formal or cold or impersonal, and therefore not appropriate for a recreational activity.