I saw this guy you may know who is really really really bad at this game....with an MMR that was SIGNIFICANTLY higher than he could ever hope to achieve on his own. Now, I know this guy well enough to understand he's far too poor to pay for a boost....which left cheating the system in some manner or another. With that being said and my chicken still thawing I figured I would kill some time and figure out how this could of happened.
Turns out it was pretty easy to determine. The guy was playing with people who literally have OVER 3,000 less MMR than him and, from the looks of it, were tanking their MMR on purpose in games without him so they could duo up and artificially boost his mmr.
All of the below screenshots are of Hero League only (no QM or TL included).Here's some pretty concrete evidence (shits pretty funny lol).


TLDR: Bads will always be bads ahahahahaahah