You know, I read this initial post earlier and misinterpreted it. But now I think the author may be wrestling with the same hurdle we have been re: "hiding Notebook posts" globally.
You have to segregated Notebook posting to a separate scene and then build some kind of toggle switch to get your user in and out of the segregated Notebook-only layer or layers. This proves rather daunting, I'm not going to lie. We built out a scene switching mechanism to do this but it's clunky for the user because when they're using Notebook they have no reason to understand they have to go through another step to get to and from the separate scene because to the user/player, scenes are invisible, even though to you the designer, they are essential demarcations for the action.
As a sidenote, depending on how much data you expect your user/players to upload via Notebook, think very carefully about how much you rely on it. We just ran into a huge problem that would have been exacerbated by inviting users to use Notebook to post videos because it turns out that all that data (not sure precise threshold of instability--it seems to vary per device) will prevent your game from loading after a time (~100 MB +). As a result, we stripped a lot of media from our game to make it stable on older devices, and I am in the process of stripping out the components that promote use of Notebook and separate it from our primary game and curated content delivery scenes.
So take the following recommendation with that grain of salt and private message me if you want to discuss further.
What we did was use a conversation as a toggle to and from a Notebook segregated scene, giving an attribute to the player/user to trigger the scene. The hard part from a user flow standpoint is getting them to pick a different conversation on the way back to take that attribute from them and route them back to your main action scene. This gets ucky. We pinned these to the Tabbed Menu and locked them according to the various attributes in question, but the Tabbed Menu likes to crash ARIS if you get too creative with it and we ran into other user flow hurdles the more I solved the Notebook segregation problem.
If this makes sense, hopefully it is useful to you. I am not aware of a global setting that can toggle Notes on/off, although I agree that would be useful. Right now, we would basically toggle the user state on/off relative to a scene where user posts would aggregate and keep them separate from the main map.
Final note: because of the data and UI hurdles involved here, we are opting to invite our users to post content with a hashtag and allow others to worry about hosting the voluminous data associated with user media posts. This does not give you the geocoded aspect within ARIS, but it prevents the game from crashing if it becomes too popular. This assumes that you, like we do, care about video posts from your users. If you're only using text posts, then you probably don't need to worry about data overload.