Crop Circles to me don't seem to be a part of this reality to convince people of alien life, it seems they are here to make (some) people doubt current beliefs about reality. If this phenomenon were meant to convince people, the symbols would be burned into mountains and market places. Which would probably cause mass hysteria.
It's likely that some readers will feel aversion to crop circle material, because you've probably heard about folks making them themselves (the Plankers), well breathe and check out this excerpt:
"Even the Plankers themselves don't claim that they've made all of them, although they water it down a bit; words to the effect of: "Well, no we don't know who made that one, so there must be circle-making gangs that we're not in touch with." (Matthew Williams- CFZ Weird Weekend 2006) The Plankers are actually every bit as much “New Age” and "freaky" as most of the “croppies”, people like me who study crop circles as a paranormal phenomenon! They regularly report paranormal activity while they're making the circles. They carry out pagan ceremonies at their circlemaking sites too."
Some more alien self brainfood:
* Terence McKenna Live at St. John the Divine's Cathedral, Synod Hall April 25, 1996
Not from the page but my memory:
"People are so alienated from their own soul that when they meet their soul they think it comes from another star system."
"I once discussed this with the Mushroom who said, we are disguising this as an alien invasion as to not alarm you to what's really going on." Terence McKenna (paraphrased)
* Guerilla Ontology
"My observation of the Universe convinces me that there are beings of intelligence and power of a far higher quality than anything we can conceive of as human; that they are not necessarily based on the cerebral and nervous structures that we know, and that the one and only chance for mankind to advance as a whole is for individuals to make contact with such beings."
Crowley (1944) Plan 93 from Outer Space by P.R. Koenig
"Fiction, as a vehicle, has often been used by occultists ... Ideas not acceptable to the everyday mind, limited by prejudice and spoiled by a 'bread-winning' education, can be made to slip past the censor, and by means of the novel, the poem, the short story be effectually planted in soil which would otherwise reject or destroy them."
The Magical Revival by Kenneth Grant
* Here are some great UFO quotes that shed light on the deceptive nature
of the "alien" presence:
"But the UFO phenomenon simply does not behave like extraterrestrial visitors. It actually molds itself in order to fit a given culture."
See the rest here.