Stay Behind Meaning

Example: Alternative form of stay-behind
1861, John Hart Dunne, From Calcutta to Pekin, page 95,
  Pleasant prospect for us, who are sure to be amongst the unlucky stay behinds!
1992, David Drake, Bill Fawcett, Battlestation, page 134,
  â€œ […] Think there may be some bugs left. Deserters, stay behinds, whatever.”
2004 September, Scott Berinato, Chandra Tallman, The Art of Securing Pricelessness, CSO, page 43,
  That creates very few “dead spots” for potential thieves to avoid sensors and helps deter “stay behinds”: skulkers who come into the room with a group but remain when others leave.