A British news agency did a piece including this a few years back. They locked up their own bikes in public places, and had a "thief" steal them, doing his best to give people time to notice and intervene, and people just took a glance and kept walking.


Or, if you are more crafty, my favorite bike theft story I heard from a guy the first time I went to Amsterdam: one of his bikes was stolen when a couple thieves got uniforms and a truck that looked like the city department responsible for removing illegally chained bikes, and went down the road picking and choosing what they wanted with all the power tools usage they needed.