Good Question... I agree that not having an order by statement can cause the output to change. I also agree that the clustered index created in the script also had this affect.

I also agree that this table schema would need a re-write for a production transactional database project. Thier are several articles in BOL and other places that would point that out.

1. A table identity column should be part of the primary key for the table.

2. If a table has a clustered index, it should include the primary key.