Plus, add to the fact that these aircraft did not spend all their time at high altitude escorting bombers. When their escort duties were finished, they would cut loose and go low and "shoot-em-up" German targets all over Western Europe. US tankers did the same thing to the white stars on their vehicles (Shermans are the primary example here). They overpainted the white stars with fresh OD (I also seem to remember black being used but I may be mistaken on that) to reduce visibility from German anti-tank guns and tanks since their guns could cook a Sherman at 2000 meters (or more) and the white star was extremely visible from those distances.
Edited by Juggernut, 19 November 2017 - 07:29 PM.