Reasons to keep code secret (2)

Customers will try to modify the source code, resulting in new problems that could be difficult for either the customers or developer to correct
The source code could be used as evidence in legal proceedings, particularly those related to whether the developer has been complying with certain legislation or court decisions
The source code could contain unfavorable comments inserted by programmers about their employer, customers or competitors

Customers will try to modify the source code, resulting in new problems that could be difficult for either the customers or developer to correct