If no restrictions are imposed, a proxy user could use a SET QUERY_BAND statement to change the proxy user for the session and possibly make unauthorized access to the database. However, use the GRANT CONNECT THROUGH statement and the WITH TRUST ONLY clause to instruct the database to honor SET QUERY_BAND statements that set or update a proxy user only if they are part of a trusted request. You also must program the application trusted user to flag each request as trusted or not trusted to prevent unauthorized use of SET QUERY_BAND to change of the proxy user for a trusted session.