The witness was given 'blanket' protection from prosecution. [=the witness would not be prosecuted for anything]
The job was her 'security blanket'. [=the job was the thing that made her feel safe and secure]
A 'blanket' of gloom spread over the crowd when they realized their team would lose.
(..) and pall thee in the dunnest smoke of hell, that my keen knife see not the wound it makes, nor heaven peep through the blanket of the dark to cry, "Hold, hold!" Hie thee hither that I may pour my spirits in thine ear and chastise with the valour of my tongue all that impedes thee (..)2015 Macbeth