As a non gov entity the company and it’s employees are not
bound by the same legal restraints. They CAN pretty much
show up as they wish.....and you at your home and management
at your place of business can just as rightfully tell them
to depart forthwith and with haste or be arrested. If they show up unannounced, uninvited and unwanted and are told to
leave immediately and fail to do so they are then trespassing and NEED to be arrested.
The Fourth Amendment says nothing about government entities.
I was once told by a government law enforcement official that a private citizens can beat a confession out of a perp and turn the evidence over to police and if they can go and get additional evidence they can make the arrest stick. Forced confessions are not allowed by government but no such restriction exists for private citizen. The private citizen would be liable for assault however. The case involved a family that had a child raped. They kidnapped the person that they knew did it and beat him until he confessed. The evidence gained from the confession showed he had done it and he was prosecuted.