Afaik they didn't. However, a lot of good Reddit players started to check out to where and whom they connect, as games started to feel weird and very competitive. Guardian.gg then showed them that they mostly connect to people in the same Elo/KD range, while checking out where their connection goes, allowed them to see that they are now getting connected to players literally on the other side of the globe. They went further and then created new PSN/Live accounts, without any skill data on them. Subsequently, they got match made with people who allowed them to have 40 kills+ per game, with an obscene KD. Until a certain threshold is overcome, and those new accounts then get matchmade with similar KD/Elo players. So the proof itself is in the pudding. I do not remember Bungie explicitly denying or confirming this tho.