One of the signs of Alien Life visiting Earth has been mysterious crop circles. For argument's sake let us assume that aliens are real and they are leaving these behind.
Crop circles generally appear at night when it's logical to assume there is less activity in the area as humans are recuperating. This would suggest that our space visitors want to do what they want to do on earth (observe us sleeping, relax under our sky, steal shit) when there are less prying eyes.
Assuming this is true, then why would they leave behind evidence where they landed? Why not land somewhere that leaves less evidence like a field not covered in stall stalk of crop like corn or wheat, or even try and hide it by blasting the place so it destroys the crop circle and leaving behind a rock so it looks like a freak meteor strike?