Failure to notice surveillance (9)

I believe the answer is:

oversight

I believe this clue is a double definition.

'failure to notice' is the first definition.
(I've seen this before)

'surveillance' is the second definition.
(thesaurus)

(Other definitions for oversight that I've seen before include "Neglect" , "what supervisor has" , "error" , "Slip-up" , "Mistake resulting from inattention" .)

I've seen this clue in The Telegraph and The Globe and Mail.

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