I was running a culster named "cluster_green" with 5 servers (4 main servers and one arbiter).
I deleted all the databases (rm on disk) on the four main servers, but left the 5th server (the arbiter) unchanged.
I then configured the four main servers to use a different replSet called "green".
When I restarted the arbiter, configured to replSet "green", the server crashed.
(see attached log file)