Andrew Gray wrote:
To the best of my knowledge, the United States does not
possess any
"royal parks". Given Stephen appears to live in the UK, a country
which does have royal parks, it seems reasonable to assume he shot the
videos there. In which case, the question of what American laws apply
to the filming seems a bit less relevant.
While the person filming has to worry about the law regarding filming,
anyone redistributing the films in the United States does not---it is
not necessarily illegal to redistribute illegally filmed video. This
came up a while ago on Commons with World Cup photographs: The stadiums
prohibited photography, but given that photographs were taken and
uploaded under the GFDL, Wikimedia is violating no law by continuing to
host them. The original photographer likely violated the prohibition,
but that's a separate matter, not enforceable through copyright, and so
not really our problem.
-Mark