flying picket vs lie-in

flying picket

noun
  • A person or group of people who can be rapidly deployed to different locations in order to picket workplaces (take part in blockades or other protests) during an industrial dispute (dispute between workers and employers). 

lie-in

noun
  • A form of protest where a group of people lie down in a public area. 

  • A period spent lying in bed for longer than usual after one has woken up. 

How often have the words flying picket and lie-in occurred in a corpus of books? (source: Google Ngram Viewer )