The introduction of a Chromecast broadcast notification, which shows up complete with play, pause and stop controls on any device connected to the same network as the device being cast to, has been lamented by many since it showed up December last year, but now it seems Google is about to give us the means to turn it off.
In a support document Google is outlining the steps to turn off the cast notification, but unfortunately it doesn’t appear to be live for anyone just yet. The process looks like it will be quite simple when it does go live however with the support document giving these steps:
Turn off Cast media control notifications for a Chromecast or Google Home device
To prevent others on your Wi-Fi network from controlling your media casting, you can turn off Cast media control notifications on the Chromecast or Google Home device.
- Open the Google Home app
.
- In the top right corner of the Home screen, tap Devices
to see available Chromecast devices.
- Scroll to find the device card for the Chromecast you’d like prevent sending cast notifications.
- In the top right corner of the device card, tap the device card menu
.
- Under Device info, turn “Let others control your casted media” off
.
.
to see available Chromecast devices. 
.The change is likely related to one of a number of Google services including possibly Google Play Services, so we may need to wait for that update before we get access to this.
I think we’ll still be leaving ours enabled…..it’s one of the “features” we enjoy by being able to add to playlists and tweak volume settings or what content is actually casting between devices and family members.