I'd just like to make one comment here about the this article. Of course, the Empire State Building was lit up in red, white and blue and it most probably as in welcome to Will & Kate but it is hardly something new. Those are the same colors as our stars and stripes and IIRC, it was also lit up that way for the 9/11 anniversary.
I would think that the Cambridges' found it a pretty warm welcome though. From some pictures that I saw, there were a lot of people waiting to greet them at the airport waving the Union Jack.
Empire State BldgVerified account @EmpireStateBldg
We welcome Their #Royal Highnesses The Duke & Duchess of Cambridge by sparkling in red, white & blue. #RoyalVisitUSA
https://twitter.com/EmpireStateBldg/status/541713456177872896