Here's someone else using the same name admitting they've cheated before:
https://halo2.online/threads/i-am-very-sorry-for-the-use-of-cheating-i-promise-never-to-use-it-again.1909/#post-10074
Yep, I was in the same game. Looks like my recording didn't work (it just got audio and a black screen), but for what it's worth I saw them tank two grenades going off directly under their feet. Shame too, the whole server just left after that and I actually wanted to play zombies.