Rated Battleground MMR Exploit (Patreon)

A rated battleground team has been using the following exploit creating some controversy:

A team with mostly high Match Making Rating ques with one character with 0 rating, significantly reducing the team's  average rating, and allowing them to play against low-ranked teams.  The zero rating player quits before the game ends to prevent him gaining rating. 

The exploiting team can grind up slowly but consistently with this method.

Any one using this method currently is  running a risk of some kind of Blizzard countermeasure. In the longer term more subtle variations around the same concept are likely to be effective.