Licensors are generally reluctant to allow access to source code. They want to insure continued revenue by making certain that licensees have to come to them for updates. They also want to insure that no one can steal the program and compete with them. Getting a copyright may not be adequate protection for source code. Copyright laws prevent copying the expression of an idea, not the idea itself.
Many source codes reveal a particularly novel, unique, or brilliant way to approach a subject.
Once a programmer understands this approach, it is relatively easy to write another program that is similar, but different enough to avoid any copyright problems. Both users and developers have interests to protect with respect to source codes. One way to deal with this problem is to allow the licensee direct access to the source code, but require it to adopt strict confidentiality measures. From the licensee's point of view, direct access is the best approach because it allows the licensee maximum control. To negotiate one of these contracts, the licensee must be prepared to sign clear and meaningful confidentiality agreements.