Yep, I remembered wrong when I commented earlier. Apologies, forgot about shared Proscan feeds.Proscan can monitor other ProScan feeds if they are public. There is a place under Remote Scanner over IP where a feed can be "published". If you are looking to monitor those, you would choose Update in that same tab and a list of published feeds appears.
When someone sets up a ProScan feed this way, they can choose how many users can be on it at the same time and if they can have control.
Keep in mind that it is a very small number of ProScan users that set up this way.