I see students posting their entire essay, including the name of the college on CC for advice and input. Is anyone ever worried that their essay will be used by someone else? It would be awful for the AO to receive 2 of the same essays. My guess is that both people will be rejected if caught.
Not a smart move for a lot of reasons.
In the years I’ve been involved on this site, I have yet to see an essay posted that did not suck. If someone stole that essay, they get what they deserve. If the OP sent that essay, it would not enhance the application.
But yes, people should not post their essays.
It seems to be more international students doing it than American students. I usually flag it, and it gets removed. These kids just don’t realize the consequences if TurnItIn or some similar program calls it out as plagiarized.
LOL… 
There is actually a pinned thread on the essay forum telling people not to post essays.