I've had plenty of problems with trespassing. Just this past week when I was at my property someone came onto the place via horseback. Granted I had left my gate open however my place has "No Trepassing" signs all over the place. People just don't seem to care.
By the way for you fellow Californian's here's the current law in CA...
California Penal Code 602.8
602.8. (a) Any person who without the written permission of the
landowner, the owner's agent, or the person in lawful possession of
the land, willfully enters any lands under cultivation or enclosed by
fence, belonging to, or occupied by, another, or who willfully
enters upon uncultivated or unenclosed lands where signs forbidding
trespass are displayed at intervals not less than three to the mile
along all exterior boundaries and at all roads and trails entering
the lands, is guilty of a public offense.
Personally I have stuck with the posting signs every 50 feet or so and signs on all of the roads in and out of the property. Although it has cut down on trespassers (and stopped people from cutting my fence which had happened before) it has not eliminated trespassing.
LEGAL DISCLAIMER:
Jeffhasapond is not an attorney and is not in any way licensed to practice law in California, or any other state, region, county, US possession or territory, foreign country, tropical island or even in France. Although Jeffhasapond did watch almost every episode of LA Law, he is not qualified to dispense legal advice. Accordingly, any posting by Jeffhasapond that seems to contain legal advice should be regarded as mindless dribble to be scoffed at or ignored.
