Remember if you connect to SQL Server using Windows group, you cannot define a default schema. It is greyed out. This means that if you want everyone to be in a specific schema, you can't do it by default.
I hope finally MS will be addressing this issue in the next release of SQL Server named Denali (CTP 4)
I'm happy to report that the next CTP for SQL Server Denali will allow default schemas to be assigned to Windows groups.
I'd like to thank everyone for their votes and attention to this issue. It made a different in being able to appropriately prioritize and make this improvement happen.