Many types of public address systems use a "prompt" to get your attention before relevant information is given.
A "ding dong" noise or other sound/voice ("attention shoppers...", "This is your pilot speaking, ...")
It is NOT important what it is as long as you can then "tune in" to what is being said, to hear the core message after this prompt.
For me when flying it is the word "traffic" at the start of a radio call which gives me the prompt to listen to the call.
The next word is the "location". This determines whether I need to keep listening or not.
If not, I can tune back out and do whatever it was I was doing before hand.
If the word "location" becomes the prompt, it is a pain because half the time I miss it, and have to listen intently to the end, to hear the location again.
Then find out the "location" was a strip 50 miles away and I listened to all that for nothing.
So..... "traffic" then " location", in that order, is just pure common sense...... irrespective of the regulation.
And where do regulations come from? God? Some almighty being? Satan? The alcoholic that lives on the corner? Nanna's dog?
No people, they come from HUMANS. And humans are often wrong.....