What I think would be cool, is if we could put “private fields” on other peoples observations. For instance, if I was wanting to exclude certain observations from a range map, I could apply my private field “location inaccurate” and then use that to filter out the ones I felt were questionable. When I create a field, I would have the option to make it a “private field”, meaning it can only be used by me, and only be SEEN by me, so it would only appear amongst the fields on an observation if I am looking at it, others would not see it. That way, we have TAGS which are useable on your own observations only (but visible by everyone), FIELDS which are useable on everyones observations (visible by everyone), and PRIVATE FIELDS which would be useable on everyones observations (but only visible to the owner of the field).
When I first struck observations that were appearing in projects, but the project was not appearing in the list of projects that the observation belonged to or appeared in... I was somewhat disconcerted... I like to know what my observation is used for! But after a while, I kinda relaxed on it, and it's actually good having it visible only if I am a "member" of that project. Perhaps this idea of "private fields" could work in a similar way, and you only get to see the private fields if you "follow" the owner of them. Maybe there could be "Project Private Fields" that are tied to a project rather than an account, and only those that are members of the project can see them.