I don’t like it. Motorbikes, especially powerful ones, are just too big to fit in them with bikes as well. Often I find theres no space whatsoever in them without getting dangerously close to a motorbikes exhaust. It only takes 2 or 3 motorbikes for this to happen, whereas otherwise you’d fit a lot of bicycles in.
Makes them kind of pointless as a safety feature for bicycles. Maybe they need to be bigger?
e.g
[video]http://www.youtube.com/watch?v=lnQnT6mFPRo[/video]
This might be a London thing due to the congestion charge not applying to motorbikes.