I am fascinated by unintended consequences. I just finished reading a
paper about the effectiveness of bicycle helmets. It seems that Australia
enacted legislation that required the use of bicycle helmets by all
bicyclists. As a result, bicycle related head injuries went down 11%. But
bicycle usage fell by about 20% due to the added cost and inconvience. So,
the overall result was that the likelyhood of sustaining a head injury
while bicycling increased with the requirment of wearing a helmet.
Further, since it is estimated that bicycling can increase your lifespan
by between 2 to 10 years, and the actual rate of head injury while
bicycling is so low, the net effect is a substantial decrease in lifespan,
at least amongst potential and actual bicyclists.
Now, I have no idea how accurate any of this is. But this is