Question: In SQL Server 2008, if you are running Profiler in a database set to compatibility mode 80, are the security requirements for showplan data determined?
Answer: The SQL 2008 interpretation is used.
Explanation: When you view showplan information through Profiler and the database compatibility mode is set to 80, the SQL Server 2008 permission interpretation is used. In this case, the compatibility mode has no effect.
Ref: Showplan Security –