Fence must be 6" from property line?

Had an acquaintance tell me this once. I didn't see why a fence should be a certain distance away from the property line in order to be legal since I should be able to put up any structure I want anywhere on my property as long as it doesn't encroach on another's property, so I called him out on his bullshite. I asked him how the hell is the fence owner supposed to maintain the rest of his/her property on the other side of the fence, to which he just looked dumbfounded.

Got a family member who's a damn good lawyer so I asked him the same question. He says that's bullshite and that a fence can be built right up to the property line as long as no part of the structure encroaches onto a neighboring property. Got a buddy who builds fences for a living and asked him - he said it's bullshite too.

But apparently everyone else I talk to says they've heard this as well and swears it's a law. What says' the OT? I'm inclined to believe the lawyer for obvious reasons but just curious as to what the OT says.