Brompton Chained to a Barrier

I was walking back from Soho today when I passed this Brompton. It was folded and chained to a road barrier near the Radio 1 studios.

Why was it outside and chained up?

The whole point of the Brompton is that you can fold it up and take it indoors and park it under your desk or in a cupboard.

I was going to nick it, but I took a picture of it instead. I had my Blackberry on me but I didn't have a hacksaw.

(Obviously I wasn't really going to nick it!)