The website says the move is to stop fans from moving across the lower grandstand to get next to the dug outs to abuse the management.
In recent weeks at least one supporter was removed from the ground for voicing his opinion on Lennie Lawrence and at last weeks home game v Colchester fans made a deliberate attempt to get as close to the bench / tunnel area as possible to voice their disaproval of the management team.
The full story can be found here on the official website.