Well in the good ole' USA when someone finishes their MACH they are showered with gifts from their admiring friends. There is much celebration and dancing. Sometimes there are parties that go WAY overboard that involve singing and poems. I won't get into that here....but some people know what I am talking about (terry and annmarie!?)
In Merry Old England there is a very ancient tradition (in case you didn't know: England is much older than the USA) that involves cabbage. I could tell you why you get cabbage when you finish your dog's agility championship but then I would have to kill you. You will have to figure it out yourself.