The title sounds a bit abnormal but we actually experienced this fiasco earlier this year with one of our customers. The candidate accepted the offer and agreed to start in 3 weeks (she was moving from another state). To our surprise and our customer’s dismay, she contacted them approximately 10 days after accepting to say she took a different opportunity.
The hiring landscape is changing with the younger generation. I have never heard of a candidate backing out of an agreed upon offer with a firm start date.
I guess I am naive because I just read this article from CareerJournal.com. Who knows, maybe the author of the question was our candidate?