One way to prevent the option of Airplaying from AppleTV to your Arc is to put your Arc on a different wired/wireless subnet to the Apple device, so perhaps put a WiFi access point or router etc;in your bedroom running on a different Subnet/SSID and attach the Arc to that.

In fact I have done a little more digging into this issue and there seems to be another (slightly more complex) way to also deal with this issue and that’s by setting up a Home in Apple HomeKit and sharing a Home with registered iOS (Airplay compatible devices, speakers/accessories) and then restrict the playback of the speakers registered to people who share your Home only, rather than giving everyone access to the speakers on the same subnet.
 

Once in place you just need to ensure the AppleTV user account in the living room is set to not share your Home in HomeKit. I’ve not personally tested this feature, but by all accounts it should work and seems quite easy to setup.. See screenshot from my Apple HomeKit settings. You can even add password protection to the setup.

So this eliminates the need to perhaps buy any additional hardware or having to divide the network.

Hope that helps.

It’s actually the air play feature. Sonos does not allow us to turn off. I as iOS user don’t even use it or need it. I called apple and they Sonos is the only one who can turn it off with a firmware update.

Just add an Airplay password in the HomeKit App - there’s no way anyone can Airplay to your devices, if you don’t provide them with the password. See screenshot.

Because I have 2 Apple TV’s. It would be useless since I’m the owner of both and the keychains with passwords would still have access. The best way is to just shut off air play which isn’t an option from Sonos right now. 

I don’t understand what keychain has to do with this? - you merely set the Airplay password in HomeKit on your iOS device. No need to store that password in keychain, but even if you do this, how would any other user get access to your keychain? Also, how would another user get access to your HomeKit Home, as long as you don’t share it?

I understand what your saying. But not what I’m after I want the ability to turn it completely off. Some of us who own an arc would like that feature. Simple no arguments.

But... all a user within your Household will do, with access to your WiFi or wired network, is play music from the Sonos App, or they might ’cast’ audio to the Arc from Spotify, or use the Amazon Music ‘connect’ method instead of Airplay… there’s no way you can block them playing music loudly at anytime, either accidentally, or on purpose.

The only way to do that is to have devices on separate network subnets and that might be a nightmare for everyone concerned.

Arc and all Sonos speakers are a ‘networked shared’ device… anyone on your "secure” local network has access to it. You’re not going to be able to prevent that unless you put the devices on a LAN that only you have access to.