Today, we permanently banned 90,000 smurf accounts that have been active over the last few months. Smurf accounts are alternate accounts used by players to avoid playing at the correct MMR, to abandon games, to cheat, to grief, or to otherwise be toxic without consequence. Additionally, we have traced every single one of these smurf accounts back to its main account.
If the account is not at roughly the same mmr it seems reasonable to count it as a smurf