Nah. Any real USPS worker being told to interfere with US Mail would immediately report their supervisor to the post office police.  It is a felony to interfere with the mail, and a supervisor telling people to would be immediately fired, and hopefully prosecuted. A simple "Fuck you, I'm reporting you" would get a) whistleblower protection (as that really matters)  and b) a piss their pants supervisor who would be very afraid.