I perform a geological survey on hill and see it unfit for human habitation due to excessive risk for landslide. Current residents are vacated.
However, I cover it with tarp and sandbag it in place. The hill is now safe For saving the hill and eliminating the threat of disaster, the mayor grants the hill to me. Fearing another owner would give it improper care, he assures me none other than I will own the hill.
I go back in time before 5 years before the OP claimed the hill, and placed my flag there. I armed it with flying cyborg ninja monkeys (which bodies are made out of diamond-coated steel) shooting bananas out of floating eyes hidden in their hands. I also set up mirrors around the hill, so if someone attempted to take the flag, the monkeys as a last resort, could shoot a laser out of their mouth while screaming SHOOP DA WOOP into one of the mirrors, reflecting the lasers around the area, basically incinerating everything inside, and make random events occur, such as the ones in http://www.youtube.com/playlist?list=PL2B33CA4B03917C1B . I then go back in time, and kill my grandmother.