Possible!

See => https://docs.oracle.com/middleware/12212/biee/BIESC/GUID-59844BCC-0EB0-4FDE-8011-75E7C8AEA82A.htm#BIESC3145

And Restricted below

What Are the Proxy Levels?

When you enable a user to be a proxy user, you also assign an authority level (called the proxy level). The proxy level determines the privileges and permissions granted to the proxy user when accessing the catalog objects of the target user.

The following list describes the proxy levels:

• Restricted Users have read-only permissions to the objects that the target user can access. Privileges are determined by the proxy user's account, not the target user's account.For example, suppose a proxy user has not been assigned the Access to Answers privilege, and the target user has. When the proxy user is acting as the target user, the target user cannot access Answers.
• Full Users inherit permissions and privileges from the target user's account.For example, suppose a proxy user has not been assigned the Access to Answers privilege, and the target user has. When the proxy user is acting as the target user, the target user can access Answers.

Are you serious? R/O vs R/W makes perfect sense. To audit things you don't need to change things - especially not things owned and crated by a user.