Can't release? Employer Client IP issues?

Some add-on developers encounter problems when their clients (quite understandably) wants to protect their intellectual property. Hence they are reluctant to release the add-ons being created. This article was created to collect strong arguments for releasing, and to counter arguments against.

Positive effects:

1. Goodwill, cred, visibility: The company will be credited with supporting the community, this can be used in .
2. Further development: Other developers might use the code and contribute back to it.
3. More eyes on the code: Could result in higher-quality code.

Counter arguments:

1. Competitors might steal the technology: This is unlikely, add-ons aren't that portable. And if they did, it would have to contain your name for their customers to see. Either way, general UI-components does not give many insights into business processes and practises.
2. Security issues: Add-ons are fringe UI functionality. If security is not only client-side, but in UI add-ons, there are other problems that need to be addressed.
3. Intellectual property value: Is this technilogy so forefront and unique that it can be sold to other companies? If so, remember that web clients in general are practically impossible to protect from reverse engineering.