Some Continental soldiers struck up conversations with their British counterparts across the front lines while they were on guard duty. Mindful of the intelligence the enemy might gain from such contacts, Washington ordered the practice to cease.
"Notwithstanding the Orders already given, the General hears with astonishment, that not only Soldiers, but Officers unauthorized, are continually conversing with the Officers and Sentrys of the Enemy[.] any Officer, Non Commissioned Officer or Soldier, or any Person whatsoever, who is detected holding any Conversation, or carrying on any Correspondence with any of the Officers or Sentrys of the advanc’d posts of the enemy, will be immediately brought before a General Court Martial, and punished with the utmost severity. The General is alone to judge of the propriety of any intercourse with the enemy and no one else is to presume to interfere."
George Washington, General Orders, 15 July 1775founders.archives.gov
https://history.army.mil/Publications/Publications-Catalog/The-Canadian-Campaign/