Our supervisor issues knee jerk policies via email that not only are not in our Company handbook, but are never included. They've addressed topics such as sick days, attendance, timeclocks and uniforms, with violating consequences that range from

Our supervisor issues knee jerk policies via email that not only are not in our Company handbook, but are never included. They've addressed topics such as sick days, attendance, timeclocks and uniforms, with violating consequences that range from written warnings, suspensions to immediate dismissal. Are spontaneous email policies issued by a site supervisor valid, or supersede the company policies & procedures? Would they stand a chance in court or with the NLRB?