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.
(..) - Shit, man. Now it's all gone. - All gone. All gone. Do you know what a duvet is? - A comforter. - It's a blanket. Just a blanket. Why do guys like you and I know what a duvet is? Is this essential to our survival in the hunter-gatherer sense? No. (..)1999 Fight Club