I noticed that line 178 of org.jboss.seam.core.Init.java is commented out:

 private void checkDuplicateFactory(String variable)
 {
 if ( factories.containsKey(variable) || factoryMethodExpressions.containsKey(variable) || factoryValueExpressions.containsKey(variable) )
 {
 //throw new IllegalStateException("duplicate factory for: " + variable);
 }
 }

Is that intentional? Seems like users should be warned if they try to make two factories with the same name.