Background
We have several video conference rooms in all regional offices. They are regular conference rooms (which are used for video conferences but also often normal, local conferences), accessible and open to everbody, anytime.
They are reserved in our Exchange, and all reservations are clearly visible for everybody; i.e., everybody can quickly and easily check who is in which vidco room.
From each video conference unit, one can easily (no password or anything; no reservation necessary) dial-in into any other vidco unit. Originally, voice and video would be immediate open bi-directionally; recently that was changed so that only the video stream appears but the microphone on the called side is muted (and has to be un-muted in the target room).
Active cameras are clearly visible; they sit prominently on top of the displays; when offline, they are pointed to the side with a red LED; when active, they swivel into the room and show a green light.
Question
Aside from the fact that we are working in IT and are all somewhat more or less involved or interested in data security topics: is there a possible problem here, involving law or potential law suits? I mean, worst case something really private goes on in a room, and a 3rd party simply snoops in. To stay in a business context, this could be secrets written on a whiteboard or whatever else you have (you can think of more or less humorous interpersonal things for yourself ;) ).
I would like to have some objective and possibly un-attackable arguments for our facility management or even higher-up to change the situation (i.e., make the video calls opt-in on the receiving site). As there is probably significant cost involved, I do not want to make an issue without first being sure to have a "carrying" argument.