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.
(..) that gives me the sense of purpose. It's not all about the money. Money can keep you warm. It pays your heating bills, you know. It can buy you a blanket. But it's not as... Doesn't keep you as warm as when my husband holds me. Let me get up. Let me get out. Let me find something. (..)2009 Up in the Air