It looks like this option does exist (https://issues.apache.org/jira/browse/HADOOP-4944).  I think I like this separation of concerns and will give it a shot.  

If this works, then I think there should be an option like "reset-user-conf" that defaults to false and wipes out any and all configuration when the tool runs.  This way there's a convenient way for users who've misconfigured their clusters to press a "reset" button and start from scratch.