What is the effect of a scout standing at an enemy barracks?
Military bonuses can be blockaded, but not stolen. So you get the trade, but nobody gets the combat advantage.

Source Blockading a Great General (Board Game Geek), from the the designer


  Military bonuses CAN be blockaded, however, scouts CANNOT steal
  military bonuses (military bonuses weren't originally icons, and I'm
  pretty sure that could be game breaking).
  
  Scouts can send home anything they're on top of except wonder
  abilities and military bonuses (even in another player's outskirts,
  even on top of a wonder, building, or great person).