Unless of course they are growing us for a food source!
I'm sure the millions of cows we grow for food have no idea it's really all a big Conspiracy that us humans are perpetuating on them. If one cow suddenly told his friends and family that he thought the humans planned to eat them all, the other cows would laugh and laugh at him and call him a nut job.
Depending on where you do your research (FBI, CIA, Conspiracy sites, news articles) You'll find that aprox 2,300 people go missing everyday.
I believe it was the FBI's website that put the yearly estimate at 895,000 people per year!