I'm in favour of cyclists occupying a lane, especially on narrow roads to take full control and I do that myself often. What I dislike is when they have their own lane and then ride 2 or 3 abreast so they don't fit and stray a foot or two into the car lane as well. It's the worst of both worlds. Even worse when they drift into the car lane without looking back to overtake other cyclists, which seems to happen regularly around here.