It depends on the union. For public safety purposes, we are highly regulated, and many, many of our employees carry specific certifications in order to undertake certain tasks in the industry. If some of those people were to withdraw their service, and we had no way of deploying management or other people who were appropriately certified to do those jobs, then you would essentially shut down the operation very quickly.
On December 7th, 2006. See this statement in context.