Works Made for Hire - Independent Contractors Own their Copyrights

We train our clients in how to register their copyrights with the U.S. Copyright Office.
Something that came up in such a training session the other day is worth repeating here.
Employees that create original works for their employers (articles, artwork, designs, etc.) do not own the copyrights to those works. Their employers own the copyrights under the Works Made for Hire or (Work for Hire) rule.
However, independent contractors do not follow under the Work for Hire rule unless the contractor and the company that the contractor is working for have an agreement that the contractor's work is for hire.
In this day and age, companies are hiring more and more independent contractors on a project by project basis. Sometimes the projects can the creation of critical property for the company, such as source code for software or web designs.
The independent contractor owns the copyrights to that work unless the company that hire the contractor obtains an work for hire agreement to the contrary.
Get those contractors to sign work for hire agreements!