Ну так там же ясно написано:
any user can restore a database as long as they are not restoring it over an existing database. A restored database file belongs to the user ID of the person who performed the restore. This means that backing up and restoring a database is a mechanism for changing the ownership of a database. It also means that an unauthorized user can “steal” a database
by restoring a backup file to a machine where he knows the SYSDBA password.

1 - кто такие остальные? Ты ж когда им права раздавал, так на ту базу раздавал, что у тебя была, а восстановил в другую. Используй роли.
2 - ну в доке чёрным по белому об этом ...