Sorry to tell you this, but many (not all) of the top rounds are STILL bunk. It's true, they look legitimate, but a few days ago I checked out about 6 different guys -- names you often see on the leaderboards -- and only ONE of them was not glitching. Mind you, this is me just going into their player channel and picking a long game and FF'ding. The fact that just doing this and seeing them glitching (note: when I say glitching it typically means camping in spots where the zombies can't reach you, but you still rack up the kills) suggests how rampant the practice is. Just because it LOOKS real doesn't make it so. Load up some of the "top" guys gameplays and you'll approx. half are frauds. (Note: As far as I know most glitches don't work in survival mode, so those scores are all likely legit).
In fact, I'd say these glitchers are far worse than the 214 losers, as that is patently obvious and comical -- these glitchers you have to manually observe their gameplay to catch.
The only way forward is to wipe clean the leaderboards (never gonna happen) and patch the glitches (don't hold your breath). People who glitch are beyond pathetic, especially those who have the skill to play legit -- but what are you gonna do.