It's not a black/white situation. It's a 'argue in front of a judge' situation. With sign: Unassailable evidence that tresspassers are informed they are not we

It's not a black/white situation. It's a 'argue in front of a judge' situation. With sign: Unassailable evidence that tresspassers are informed they are not welcome. Without sign. Owner word vs tresspasser word. The latter is a weaker stance.