Teenagers doing crop circles: It's a stereotype. It's like saying that all gays have a voice like a blown turbo or that all blonde women are ditzy eejits. It's patent guff, like all stereotypes and caricatures. They are gross exaggeration. Don't take it seriously. I can imagine that it's complicated to make and it requires a clear head to do a crop circle.
I still don't see why woo-woos think that it's aliens. I suppose they'll start sending us USB drives with Microsoft Word files on it seeing that any extraterrestrial being would of course use our language system according to justintime's source

Stupid and pompously arrogant beyond description to assume that ET intelligence would use a socially-constructed system of expression that was invented by Earthlings.
The debates rage on about the existence of ET intelligence. What is known is that we are not being visited by any. Or at least there is no evidence that can actually stand up at a whiff of critique and analysis. The "UFOs" that are classed as UNIDENTIFIED are simply that - unknown. Most are typically astronomical or terrestrial phenomena, specifically Venus and planes.
Attributing an unknown to another unknown is fallacious and requires a leap of logic bigger than Becher's Brook at the Grand National.