Currently, the default department for an account created via an e-commerce public purchase is set either:
at the global e-commerce settings level, or
via coupon codes.
It would be great to be able to set this at the level of individual courses, as well. E.g. Users who purchase Course A are assigned to Department A, as defined in the course's Enable E-Commerce > Allow Public Purchase settings. Course B has Department B set as the default department.
If no default is set, the system default is used. Even if a default is set, a coupon code would override the default setting.