I find absurd the suggestion that someone who can not occupy two seats can get a second one for free. However, I find this mention in the article completely outrageous:
...<lawyer> she said her client, Calgarian Linda McKay-Panos is happy to work with the airlines to develop a "fair" process for deciding which passengers get a second seat, because of obesity or a need to have someone there to assist them during a flight.
I want to have my wife and kids with me to assist during the flight, but I always get charged for their tickets...