The original Flagbearer text tried to constrain the target selection for
  spells and abilities that could target them, but it was unclear whether
  that constraint also affected spells and abilities that change targets.
  Nowadays, the wording is clearer:

    Standard Bearer  {1}{W}  Creature - Flagbearer  1/1 
  / Whenever a spell or ability an opponent controls is put onto the
    stack, if that spell or ability could target a Flagbearer in play
    but doesn't, that opponent changes one of its targets to a Flagbearer.

  This triggers once each time a spell or ability is played or copied.

Some parts © 2009 Advameg, Inc.