Posting signs is the ONLY way to protect urself LEGALLY from trespassing.
In Florida, you must have ur yard fenced with at least 5 bobwires, Signs need to be spaced out in plain sight along the entire perimeter, not just at the entrances.
Once this is properly done, a citizen is allowed to protect his entire property from intrusion, including police (unless they have a warrant). No person without specific permission may cross my threshold. It used to be that you could only protect urself in ur own home, but Florida saw the light and extended it to ur entire property.
Walk on unannounced and you may get carried off. Walk on armed, and it's a guarantee.