Roland Perry wrote:
I saw one in Lausanne recently, where a chap was assiduously filling up
empty racks from a trailer (I did wonder what the carbon efficiency of
that was in the event he drives a few miles to deliver just one bike...
but no doubt over time it works out.

Lausanne is built on a rather large hill. I imagine all the bikes drift to
the bottom, so some kind of rebalancing is required. I imagine that isn't
so much a problem in London or Paris, though perhaps they will end up
congregating at other places?

Cardiff has the beginnings of a similar scheme:
http://www.oybike.com

Theo
(who notes that the Lausanne metro has a special section for bikes, which
might help with the hill problem)