Our ODAC with Net option in no way influences on necessity for you to license Oracle. For Oracle server it is no difference how you connect - using OCI or Net option. We are not the only who offers working without Oracle client and we don't find any violation there.
Also we consider Net option as an addition for working by OCI as Net option has some restrictions and unfortunately we cannot ensure its compatibility with all server version and ODAC users always have an ability to return on OCI.
Another question is, does Net option support full function of Oracle 7, 8, 9, 10g?
Yes, ODAC Net option supports Oracle 7, 8, 9, 10g with some restrictions, see documentation for details, and we tested it only with servers under Windows and Linux.