Prohibido el paso
A lot of people with property near the first farm I was at in Amado, Arizona had prominent No Trespassing signs at the entrances to their property. I suppose that if you're some impoverished Mexican who's just spent a couple thousand dollars and two weeks tramping through the desert to get into the U.S., a No Trespassing sign would *really* be a powerful inducement to uh...just stay away. I mean, especially if it was in Spanish and all. Right?