Mountain Eagle initially thought that those Europeans and Americans were sent by the United States Embassy for negotiations...
But after talking to them, he realized that these European and American guys were actually journalists from England, and quite famous investigative journalists at that.
Under the guidance of a bona fide lawyer, they would go to interrogate the American soldiers. The secret recording equipment they carried would document the testimonies of those soldiers.
This was a classic case of using the enemy's spear against their own shield; criminal immunity allowed these American soldiers to behave recklessly near any overseas base.
They were not afraid of local laws, but they were terrified of exposure, as public opinion would pressure the military's upper echelons to deal with them.
This was where Thailand was at a disadvantage...