Should Transit be Free?

Jarrett Walker at Human Transit has an interesting article about the free-fare experiment in Guangzhou China.  They are hosting the asian games this year and in order to ease traffic, they restricted driving and made the transit free.  The ridership doubled.  That was much more than the capacity of the system and delays occurred so they canceled the free transit.

Some people think that transit should be a public service and free to the public.  Would that make you ride public transit instead of driving?