Your employer sending employees home does not have the force of law behind it. You're probably not at risk of getting shot and/or imprisoned for violating their request.
It is OK to go outside for walks if you are not in a group.
I don't think they'll be shooting or arresting anyone.
And the other linked article said they'll be lax enforcement the first few days to give people time to adjust.
Where that balance is, I don't know. That's why we have the courts, to begin with.
For the Federal Goverment: https://en.wikipedia.org/wiki/Public_Health_Service_Act
The list (for the federal government) of diseases is managed via Executive Order [PDF] https://www.govinfo.gov/content/pkg/FR-2003-04-09/pdf/03-883...
The CDC also has a link to this: https://www.cdc.gov/quarantine/aboutlawsregulationsquarantin...
These measures have precedent, so good luck in getting these overturned.
https://www.supremecourt.gov/publicinfo/press/pressreleases/...
“The Court’s postponement of argument sessions in light of public health concerns is not unprecedented. The Court postponed scheduled arguments for October 1918 in response to the Spanish flu epidemic. The Court also shortened its argument calendars in August 1793 and August 1798 in response to yellow fever outbreaks.”
A city just more or less put its entire population in parole.