No one is claiming they think they are hot stuff in NYC. No one claims that if you walk down 5th Ave people wouldn't say, "Huh? Who cares?" NYC is home to so many socialites and celebs, and yes other Royals, that you're right no one here probably cares too much that Norwegian Royals moved here... In fact Marhta Louise and Ari are the ones who said they were moving to NYC for the peace and quiet it offered them, since they aren't known here. The press conference was merely to share their new home with their home country so that they would be hounded my Norwegian reporters here too. The park wasn't shut down, people were still free to come and go throughout the conference, so whats the big deal?
Finally, I'm fairly positive that the Norwegian tax payers pay for Martha Louise and Aris security...not the New York City tax payers. Martha and Ari are still Norwegian citizens, they have simply temporarily relocated.
Also, I highly doubt Martha Louise and Ari are forgetful enough, or unresponisible enough to leave their one year old daughter in the back of a cab, or anywhere unsafe for that matter!