In my experience of using broadcast you don't say hey Google broadcast.
You have to click on the broadcast button in the home app, then it asks
you what you would like to say. It's then broadcast automatically.
I know we all probably use Broadcast for a variety of reasons. For me it
has been so useful. My elderly father has Google devices in his house.
He occasionally doesn't hang up his landline phone properly, so using
Broadcast I can tell him to check it...
