If I'm a 2* rider on a regular pedal bike and buy an e bike and can do the 4* speed why is it not safe for me to move up to a 4*?  Are club riders certified for particular star levels?  Do ride leaders and fellow riders monitor and comment on the skill and endurance level of other riders in the group?   

Good points!  It seems like we as riders should first sort of self-certify.  I mean if you're comfortable with handling the rate at which things are happening in a group that can be a good start to knowing that you are likely ready for that star level.  Feedback from the ride leader and fellow riders can also help.  One thing I find is that while I may be confident of my own speed and handling skills I and others in the group would notice that my paceline skills need work.  Misplaced hand signals could have consequences.  I believe Larry has led League of American Bicyclists bike handling classes.  What a good idea that is.  Thanks.