When I used to work as a field assistant to a land surveyor, I learned that this same principal applies to those orange safety vests that road/construction crews wear. A large portion of my job consisted of hopping people's backyard fences and otherwise trespassing in order to measure things. The only times anybody ever did more than say, "Oh, hi there." were the days when I forgot my vest.
For fun and profit, go buy one of those vests at Wal-Mart, pair it with some dirty jeans, boots, and a tool-belt full of crap, and then go do whatever the hell you want to. Nobody will ever ask questions.