How to know the DB user

This has always happened, back to SQL Server 2000.
Without schema, how does SQL Server know you want to put it in the dbo schema?

The only way to specify a default schema is to :

• use SQL logins (not Windows)
• run as "sysadmin"

Neither of these is acceptable

Best practice is to always qualify schema for every object reference for DDL and DML. There are clear performance benefits because of plan re-use.

Also, deliberate schema use is better for SQL Server 2005:

• tables in Data
• other tables in Archive, Staging etc
• code in schemas per client permissions: Desktop, WebGUI etc

Using the dbo schema is so last millenium :-) Links:

• Schema design - best practices?
• https://dba.stackexchange.com/q/7257/630

How do you log onto courgette? Would that username identify you?

You can check that by running

select sys_context('userenv', 'os_user') 
from dual;

The USERENV namespace can retrieve a lot of different information about the user and their environment. Find out more.