I'm not sure, the Gillingham game was actually 2 years ago and was the first chance for many fans to go to the Amex after its opening a few days earlier and looking at the sales so far not many are going
I don't think its the friendlies that are the problem, its the fact that a proper competative match can be played with no provision by the club to get the fans there despite this agreement being in place for the past 50 odd competative matches.