There were Swiss AF skins in the game before (the older AH 2.0 Bf109 shape). They did intercept both German and Allied aircraft flying into Swiss airspace. Wether that is considered enough for inclusion to the game nowadays is another matter but Swiss 109s have been in the game in the past. But of course only the ones that were flying in the said markings during the war. I do not know if the plane in question was painted like that during the war or wether it was post war.