Outlaws are sent legal IDs, lest these be discovered (9)
I believe the answer is:
renegades
'outlaws are' is the definition.
'renegades' can be an answer for 'outlaws' (I've seen this before). I am not sure about the 'are' bit.
I cannot understand how the remainder of the clue works.
(Other definitions for renegades that I've seen before include "Outlaws" , "Turncoats, defectors" , "traitors" , "deserters" .)