Not if it's applied to every place where there is congestion. In the UK moves are afoot to expand cordon or congestion pricing to other cities. In London, very few people stopped coming into the CBD for work, they just shifted modes (mainly into carpools and buses). Some retail establishments have been hurt, but the magnitude is somewhere on the order of a five to ten percent drop in sales some of which is due to a downturn in the economy.
When they implemented cordon pricing in Singapore, the critics said it would fail but not only was in successful but greatly expanded. In London, they said the same thing but it's been successful in getting 20% of the private vehicles (a smaller proportion of total traffic as commercial vehicles and taxis still go charge or no charge) off the road. Livingstone to compensate for the effects plans to expand the zone and almost quadruple its area.
Kudos to Ken, he's no urban planner but understands urban transportation and development issues better than most planners I know.