Other Possibilities
I wrote:
The creation of geometric formations or other designs in grain fields is well within the technical capability of human beings, even if it may not be immediately apparent specifically how this formation, or that, was rendered.
Emphasis added
I believe you assume that all potential crop circle fakers are simply men in heavy boots with ropes and spirographs. Ask yourself, who else might have the motivation to create these formations, and for what purpose? Might not there be rather more organized efforts than you and those who analyze these formations assume?
Is it more likely that there is some unknown group engaged in this activity, or that an alien space-faring species has spent enormous energy crossing the cosmos to entertain and befuddle humans with human designs in grain fields?
Now granted, our hypothetical aliens may have more nefarious designs - like warming our climate (just kidding; couldn't resist), or taking our water (there you might have something), and in order to distract our species while they go about their real purpose here, create these open-field doodles to distract us.
Fair enough, but wouldn't you admit, even if we consider my somewhat outlandish conjecture, that they could just go about their business without bothering with the diversion, since they seem to be (most of the time) perfectly stealthy anyway?
Or, if some of my conjecture is somewhat accurate, and aliens really are here pilfering water, women, and candy bars, wouldn't the common or widespread knowledge of such activities tend to upset the existing state of affairs? Isn't it true that there are vested interests who wouldn't want the existing state of affairs upset? Wouldn't such vested interests possibly be motivated to undertake activities which might discredit those who look into UFOs, abduction reports, vanishing candy bars, and crop circles?
Think disinformation.
Understand that those who might be motivated to engage in dis/misinformation probably are not simply men in heavy boots with rope and spirographs. They would have other resources at their disposal.
'Not saying that this is what is happening. 'Just saying that my wild conjecture is still a lot more likely than space-faring aliens crossing the cosmos to stomp grain.
If space-faring aliens really wanted to announce their presence here, for whatever purpose, wouldn't you acknowledge that there would be other, much more unambiguous and incontrovertible ways of doing so? How about an eye-popping air show over the Super Bowl or World Series? How about cloud circles? How about curing cancer?
Just for starters...
Cheers,
S