kszyhoo, I think you misunderstood the blog post (or, at least, I read it differently). What I think is intended is an achievement for "eliminating three or more opponents and winning a game in a single turn" (that's one achievement, not a list of two, distinct achievements). It could also be phrased as "eliminating three or more opponents on the last turn of a game".
Yep, right - it doesn't sound so stupid now :P
But still, it is a good example of what is worrying me about those trophies - a lot of people may do bizzare things in order to get tropies, and thus disrupting games and fun to others. Imagine 4(or more) players FFA with 'surrender must be accepted' enabled. One player is surely winning, all others surrendered. But will he accept those surrenders and end game or will he force them to play, corner and strip to one territory so eventually he can "eliminate three or more opponents on the last turn of a game" ?