Can anyone link me to that rule (provided it exists), please?
Account sitting abuse
What is it
If the Account Sitter has a stake in these non-tournament/non-clan challenge games (as an opponent or teammate), and plays multiple games from start to finish using the Account for which they are Sitting as a communal account strategically play turns, knowing that Account Sitter will not be back to take any of these turns.
A user or group of users who loosely share their accounts among one another to improve their score and gaming by means of strategically allowing others to take their turns for them at specific times, or allowing well versed and ranked users to essentially play select games on their account for them to boost their score and rank.