WTF does this mean. Literally It seems like you want to police to take the ‘no tresspassing’ sign but for some reason I don’t think it means that.
So we are left with:
A warning to the tresspasser that police will notice you tresspassing.
or
a request to the police to notice the sign and help enforce the no tresspassing.
So which is it?
Go ask the property owner?
A private property owner would not have the ability to direct the police to patrol property. Therefore, it must be a request to the police.
Yeah, it’s meant to draw the cops’ attention to the fact that if they see somebody in that parking lot/driveway/whatever, they ain’t supposed to be there.
What DDG sez. Especially when the owner can’t be there to explicitly warn against trespassing (undeveloped rural property, or just a parking lot that’s popular for late-night cruising) - that sort of phrasing tells the police that they can go ahead and clear people off the property without needing the owner to tell them in person.