The Football Supporters' Federation (FSF) has called on West Ham United to provide CCTV evidence to back allegations of misbehaviour against individual fans.
Last month, West Ham said 200 people faced football banning orders following violence during an EFL Cup game against Chelsea at the London Stadium.
Clashes broke out towards the end of the first derby match to be played at the ground, with seats and other objects being thrown.
But the FSF questioned the club's methods, citing the example of one fan who had his season ticket cancelled but was not told by the club what he had done.