When updating a workflow transition, if the name contains invalid characters (eg. " - quote or < - less than) it throws the following exception:

javax.servlet.ServletException: com.opensymphony.workflow.InvalidWorkflowDescriptorException: org.xml.sax.SAXParseException: 
The value of attribute "name" associated with an element type "action" must not contain the '<' character.

If you goto the view transition page, you can see that the name has successfully been changed despite the exception.