How about this example:
Say I am a recruiter for a company based out of California, and I attend a career fair at a university in Colorado looking for a couple of engineers. At the career fair, I get 30 interested applicants. I conduct a hasty interview and decide to "hire" them all on the spot, with a promise of a job starting a month after they graduate with a salary higher than any other employer at the career fair is offering.
Graduation comes, and the students need to start preparing for their new job. So, they all sign leases in California and pay lots of money to move their stuff out there. After Day 1 of work, my company decides to keep the 2 that they want and fire the other 28. Essentially, using the hiring process as one large screening event. So, now those 28 people are up the creek without a paddle because they were led on by the company and were able to be fired without reason.