How about detecting those who do 0 damage AND 0 heal, and then, by example, give them a "bad token", then the 2nd game in a row 2 tokens, then 4, and after an amount of token, they can either not join the queue for an amount of time (bigger and bigger if they have to be sanctionned several times), and do like in maybe league of legends, kick their account for 1 day , then 3, then a little more, and why not definitively if they always do that?
Or simply a kick from BG after 5 minutes of inactivity and the impossibility to join queue for 30 min or an hour? (and if it happens too much, a contact from the admins)