I've tried it... It seems to have reduced by ~75% the number of thefts I've had. (I used to have a bike stolen every 3-4 weeks, and now I only lose one every 3-4 months)
These are $25 bikes that I buy in bulk and just use around the city for me and my friends. They're locked with $2 combination locks, sometimes just to a plant. It really isn't surprising they go missing, but they're cheaper than a rental bike.
