American officers have observed how Chinese troops stationed at American air bases have frequently refused to shoot at Japanese raiding planes. Asked by an American officer for the reason for this behavior, a Chinese officer at Lao-ho-k’ou air base in Hupeh answered (November 1944): “Well you see, if we shot down a Jap plane, the Japs would be angry and would take revenge and return and bomb the city and do a lot of damage.”
Source: wiktionary