For those involved in layoffs who live in Illinois or Canada.
Illinois and Canada have the WARN act that requires, by law, a company to give 60 days notice prior to termination. It reads that pay of the salary and benefits for the period of time may be an acceptable compromise.
This is a state law, they must follow it.
There also is a federal law stopping any type of gag or non-disclosure documentation to be signed prior to getting your severance. Any attempts to do this is a federal crime.
Make sure if you are targetted for severance you know your rights, and make sure the human resources you work with are also aware of this.