Solomon, no disrespect intended to your views, but I think we are missing the bigger issue here. Regardless of the PGoH's ability to substantiate their claim, quite possibly being due to the deed being locked in a dusty vault, it is an accepted part of our Shard's history and, apparently, Lord Casca himself believes it to be valid.
Correct me if I'm wrong, but nowhere have I seen him challenge the legitimacy of the PGoH's claim. Instead, he has stated:
Lord Casca: Lastly I must relinquish the independence given to some cities under Lord British, such cities
Lord Casca: will hail the crown, or be outlawed!
I believe that's a pretty clear statement that he, himself, believes that some cities were, in fact, declared protectorates or independant by Lord British and he simply does not care. This tells me that he does not choose to challenge the validity of the claim but, quite simply, to abolish it.
Further, and again, I quote from his own published words:
Lord Casca: A tax collector will be around to collect your long-standing debts.
This was said immediately following his statement as to the independence of the cities. So, is he now also saying that, in addition to revoking what he clearly believes is their independence, he is also trying to collect back taxes for the years they've been granted this?
There is much more in his statements that I feel we, as a community, should be concerned about. However, these two seem to deal directly with the issue being discussed here and I, for one, am greatly concerned by these two in particular.
I am not a member of PGoH and I have no real stake in their claims other than as a member of the community. If Casca can abolish long held claims based on his say-so, claims that he, himself, seems to believe are valid, then what is next?