Its weird reading this thread because on Monday a cyclist lost her life in the streets of Montreal taking the lane on a Bixi. She was read-ended by a truck. It's very sad; but its producing a hell of a commotion with local authorities to make it safer for cyclists.
It seems pretty clear from the press report that cyclists have the right to take the lane; so it should be mass knowledge right?
But you have people, working for the city!, who do not know about the law and honk at cyclists when they take the lane. This ended up in the local news; sorry its in french. Basically the guy says "Its dangerous" and "You don't have the right"; which is totally wrong.
Un cycliste sermonné par un employé de la Ville | Marie-Michèle Sioui et Annabelle Blais | Montréal
She died right where I passed, several times .. :-( I used to park, walk & bike there, it troubles me deeply. That said though, I still take the lane when its safe. As sad as this whole thing is, I believe its a rare, yet tragic, event and should not stop me from taking the lane.
Its a good idea to know what's happening behind; for instance of you have an 18-wheeler behind it might not be wise to take the lane; especially in a downard slope, they just can't stop! For this though, you need to carry, and use a bike mirror.