I stand corrected. What @lostintejas said about the purple paint in Texas is more accurate. If you cross that tree line or fence posts with purple paint on them you are legally trespassing and can be shot. Same principle, but it’s literally interpreted as a “No Trespassing” sign as he stated.
I'm neither a lawyer nor a Texan, but I don't think the statement about being shot for trespassing is totally accurate. You may be shot, I guess, but not
legally. I don't believe deadly force is legally allowed unless it is justified in defense of an imminent and potentially life threatening attack. I think the purple paint has to be on multiple posts/ tree trunks as specified minimum intervals to establish a legal boundary line.
I think some can be shot if in the defense of property, ie, theft, rustling, ect, but not simple trespassing. As a Texas resident I certainly do not want to try it.
Just did a quick search and found this explanation.
The Texas Penal Code 30.05 Criminal Trespass provides for the use of purple paint to mark property boundaries. Purple markings are required to be vertical lines, 8 inches long and 1 inch wide. The bottom of the markings must be between 3 – 5 feet above the ground. Purple markings can be spaced no more than 100 feet apart in wooded areas and no more than 1000 feet apart in open areas. Markings must be placed in areas visible to anyone approaching the property. Posted signs are still recommended at all access points and gates.