If this were a legal requirement, the actual facebook employees would have been brought back. They haven't been, just the people contracted by CPL/Accenture to

If this were a legal requirement, the actual facebook employees would have been brought back. They haven't been, just the people contracted by CPL/Accenture to work at FB, which leads me to believe that this is not a legal requirement. It's presumably that FB said you need to ensure security to the companies, and they decided that the easiest way was to bring everyone back to the office.