Umm, this infoclip is really just an introduction to an introduction of non-compete agreements. The brevity of the introduction means that you can probably find exceptions to some of my general statements. When dealing with covenants not to compete, details matter.
But by way of review,under South Carolina law and the law of most states, non-competes which are a general restraint of trade are against public policy and void, while those founded upon valid consideration and reasonable in their scope and operation are valid. For more, read this more detailed introduction to non-compete law (using South Carolina law).
Here are some other blog posts that anyone wanting to get a handle on the basics of noncompete law should start with:
Non-Compete Basics: Statement of the General Rule (Similar to the introduction above).
Non-Compete Basics: Reasonable in Time
Bulls-eye: An Overly Broad Radius
Reality Check: Costs of Noncompetes: Action vs. Inaction