I've been working on that question for many years. In one of my publications, I identified all the articles that dealt with federal and provincial elections and had appeared in newspapers the day after the election. I also noted the time at which the media announced who would form the next government. Time after time, the media reported that the election pertained to the prime minister or premier and identified who was appointed prime minister or premier that night.
I will give you an example. When the Parti Québécois won a plurality of seats in the Quebec National Assembly and Pauline Marois was the party leader, the next day we read in some newspapers that she was the “first woman Premier of Quebec”. However, she had not been sworn in yet and no party had obtained a majority. In such a situation, the premier in office is in principle still premier and even has the right to return to the House to try to regain its confidence.
There is a problem with people's understanding of the rules. That is why I talked about the manual. This is a problem at all levels. It's not just a problem for the public. It also affects the media and how they report information. Those who contributed to preparing the British manual included not only academics, senior government officials, and political parties, but also the media. A lot of hard work went into educating the media to minimize the use of this kind of information, which is an intellectual shortcut and flows faster, but distorts the true nature of our political system.