Perhaps also a strong sense of duty and shame - after skipping one lesson they are too embarrassed to show up again. Each successive failure to respond deepens the embarrassment, making facing the instructor again an unthinkably difficult task. The same thing can happen with lack of attendance at university classes in other countries.
This is my mind. If cancellation is available through a web form, it's easy. However, having to communicate it through a conversation makes me nervous.
>“Not a Good Match”: Almost One in Three Japanese Graduates Quit First Job Within Three Years. While earlier generations saw lifetime employment as the norm, 30% of recent Japanese graduates quit within three years of starting their first job.
Looks like it used to be lifetime and now that is changing.