Is anyone's Halo 3 FFA achievements legit?

I'm starting to wonder about the last 5 achievements remaining in my Halo 3 list. I've heard so many people request that the others just "let them" leech achievements on willing-to-not-reciprocate players.

So...how many people out there with that ninja sword on their respective backs actually EARNED those achievements? There's really no way to tell, but isn't it a bit lame to falsely achieve an achievement? I guess there will always be the "lazies" as I call them. I better not complain too much, I'm sure I've done a couple of them indirectly. The preference is to earn the achievements the "correct" way most of the time though.

I'm not too worried about the Killing Frenzy, but the sword kills and overkill may be a bit difficult to achieve naturally. Unfortunately, all the good candidate playlists get vetoed. I don't see why FFA can't go back to 8 players instead of 5. Even 6 would help and make for better games.

The concerted effort awaits; we'll see how long it takes to get through the last strides of achievements.