I was on freq when the then Lt Col Goldfein (just retired as Chief of Staff) was shot down in his F16CJ during the Kosovo thing. He declared that he'd been hit, had lost his engine and was gliding. The USAF controller promptly asked if he was declaring an emergency. One of his wingmen simply announced he had ejected but I don't remember anyone using MAYDAY or actually 'declaring an emergency'. However, I do remember following 'Bammer' and 'Jammer' when one called 'come up 12345'. Sure enough, they were on 123.45 and talking in clear with coordinates etc. A Beadwindow call had no effect. The length of transmissions were probably enough for a home-on-jam missile to have had a realistic chance of success. Great CSAR though!
Sorry, minor thread drift. BV is right, they need to use the words which attract attention everywhere else in the world.