Assume Police/CPS think there isn't enough evidence/severity to prosecute so club are exercising their right to refuse admission to those suepecterd of causing disruption. The facial recognition at the turnstiles on Monday is to make sure bearers of these letters don't try to come along anyway.
From the pre-match brief:
Reckon they've got images of the Palace fans that they want to arrest and are using facial recognition at the turnstiles to match faces of those entering to the faces of those they want to nick. Those that jumped the turnstiles or did pyro last time will get nicked...