Answer:
This war poster "QUIET! LOOSE TALK CAN COST LIVES!" Is playing on the idea of the incongruity of spies or traitors that can listen in on their conversations so it's basically telling everybody not to go around saying all of their plans because if they do they could all just end up dying.
Explanation:
I'm not 100% sure that this is the answer you were looking for but I hope this helps!
