You've seen some of these crop circles. How would you transfer it from your diagram to the actual ground? How long would it take you and how many people, and how much noise would you make? How would you and your crew get to the site without tramping down paths or leaving footprints? Some of the circles appear overnight.
In that one night you and your crew would have to lay out the huge template with precise accuracy, then cut it without noisy machinery. And then, the biggest question of all knowing the egos of human beings, why has has no one claimed responsibility for the most balanced, precise and beautiful of the circles?
Unless somebody can answer every one of these questions reasonably, I don't think anyone can honestly just shrug it off as a hoax. 