I play music on my Home speaker via Spotify.
My housemate has the Home app on her phone and a Chromecast TV.
Whenever I play music it pops up on her Home notifications as if she was playing it. She can see and pause what I'm playing.
I've set my settings on Home to "allow others to cast media on this device > No" and on Spotify have selected No to "multiple people can control this speaker". And then turned everything off and on again. But nothing seems to work.
We have separate Google accounts, separate Spotify accounts, the only thing we have in common is being connected to the same Wi-Fi.
Is there any way I can solve this???! It is maddening!
Even with cast media notifications turned off users of the same WiFi network will be able to cast to devices on the same network.
If you use a separate guest WiFi network then this will stop this being an option. Google designed it this way for ease of use for family home environments.
I hope we were able to answer your question with the info provided by @Cathal_S. If you have additional questions, feel free to respond to this thread and we'd be happy to further assist you.