There are certain things we can not do on a Caltech server, and one of them is to enable a member of the general public to post _anything_ , even just the name of a group, that is visible to the general public, even for only 1 second.
The ability to remove inappropriate content visible to the general public after it's been posted and brought to a moderator's attention is necessary, but insufficient.
What I had in mind initially was to eliminate the "Public" group, and for the default group to be "Private." A moderated default group whose annotations are publicly visible, such as you suggest, could also work, if we can find someone willing to moderate it, but I'm not sure we can, so I would vote for at least having the option of making "Private" the default group.
To be clear (at the risk of repeating myself): for Caltech to be able to use Hypothesis in the online edition of FLP, both the names of non-default groups and all their data (the annotations, replies, etc. made by the members of those groups) must be visible only to the respective group members. [If, for example, a member of the general public can create a private discussion group called "Eat my shorts," and that name can appear (even momentarily) in the list of groups seen by the general public, that won't do.]
Best regards,
Mike