The abuse detection system that user is talking about does not kick in for 3 users on a shared IP who seeming accidentally participated in a subreddit another account was banned for. You would need much larger numbers or a moderator to formally acuse you of ban evasion to the admins.
The other comments in this thread make it sound like it absolutely does kick in in cases like that, and that no formal accusation of ban evasion is required for it to ban you.