Good point. Yes, closing the lower tier in particular partly enables the lower allocation. Given that Millwall clearly cannot cope with hosting a big match they should have considered switching it to the Amex.
A big game like this one brings out a lot of occasional supporters and this is what causes the policing issue at Millwall. I've been to many games at their old and new grounds as I used to live in the area and worked with Millwall fans. I was at the grand opening of the New Den against Sporting...