Warning siren worried guards back to tag immigrants (10)

I believe the answer is:

foreigners

I'm a little stuck... Click here to teach me more about this clue!

'tag immigrants' is the definition.
The definition and answer can be both people as well as being plural nouns.
Maybe there's a link between them I don't understand?

'warning siren worried guards back' is the wordplay.
'warning' becomes 'fore' (shouted in golf).
'worried' is an anagram indicator.
'guards' indicates putting letters inside (inserted letters are guarded).
'back' becomes 'g' (I am not sure about this - if you are sure you should believe this answer much more).
'siren' is an anagram of 'iners'.
'iners' enclosing 'g' is 'igners'.
'fore'+'igners'='FOREIGNERS'

'to' is the link.

Can you help me to learn more?

I've seen this clue in The Independent.

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