I find it hilarious that "Air Canada said bumping is rare." I was bumped last week on the way to a very important meeting and the woman who helped rebook me said that Air Canada regularly over-books its flights.  Moreover, while I was being helped there was a constant queuing of people who had gotten bumped from dozens of flights.  The Legislation needs to make it illegal for airlines to sell the same seat twice.  Even if someone doesn't show up, they have still paid for the flight.  If I sold my house twice I'd be arrested for fraud.