What happens if a Buyer walks away from a deal?

I have had Buyer's ask what happens if they walk away from a deal for different reasons.  I tell them they can be sued for the difference if any between the price they agreed to pay and what it might sell for to another Buyer plus damages.  

Here is an example of this situation:

http://www.cbc.ca/news/canada/british-columbia/buyer-who-walked-away-from-real-estate-deal-ordered-to-pay-360k-1.4232844