Trying to clone a repository that is not in our routing table returns an error:
$ rad clone rad:zVNuptPuk5XauitpCWSNVCXGGfXW
ok Tracking relationship established for rad:zVNuptPuk5XauitpCWSNVCXGGfXW
== Clone failed no seeds found for rad:zVNuptPuk5XauitpCWSNVCXGGfXW